i have had an injury going on 3 years and 1 month now. Like yours, mine started out minor and progressed. Seems like the problem just keeps moving to a new set of issues. I have the same dull pain in the hip and back on the right side (along with some hamstring tightness). I have gone ahead and trained through it - but it hasn't been fun.
My best source of treatments is two things:
1) smashwerx videos by Trevor Bachmayer (easy to find on you tube). He is absolutely excellent (way better than any of the chrino videos because he tells you what you want to know - why does this hurt, how to stop it, and how do i prevent it).
2) a lot of times what is hurting is not the problem but the result of tightness or scar tissue somewhere else. For me, i have discovered a hamstring injury from years ago was causing tight hamstrings = which is causing the tight back= which then causes the hip pain. what i find that works is deep message/rolling to break up that scar tissue and gain mobility in the hip flexors. I also do some light strength training.
My mistake here has been these strengthen drills works do well (often providing immediately relief) that i over do them. I have really had to learn to progress very gradually. Right now the two best strength drills that i do are
* step ups - i usually start with 10 lbs in each hand and simply find a small step or box and step up on it and back down x about 5 or 10. and do this twice. then because that starts to feel good i move up to 15 lbs per hand and reapeat (usually do a little less volume each time i step up in weight). then 20 lbs. i have been stopping there lately after learning that more is not always better. i will also move to a higher step/box - at first i do this with no weight. i should probably stop there, but again i push it sometimes and add a little. i need to add THERE IS PAIN WHEN I FIRST START but it goes down as i progress
* not sure what to calls this next one, but you prop yourself up by your elbows so that your legs are hanging free....and simply pull your legs up as high as possible (knee to chest is the idea). in fact in one of his videos, Bachmayers says if you are standing on the ground and cannot do this easily - you have a hip flexor problem (which i did). you can have some one push down on your knee as your balance on the other foot as another test of the hip flexor. if you can not resist at all - bingo you have just identified another weakness. which reminds me of a simple drill i did in the beginning where seated at a desk simply raise your knee into the desk and push - this will help strengthen that hip flexor. as you get stronger - the handing version of this can be done - with light, light weight added. maybe 5 lbs at first. i am up to 10 lbs now. first time i did it, i was so sore the next day - so keep the reps short - a few as 5 per set with only 2-3 sets first time.
* the other big thing i do is rolling, but not rolling the way most people do it. one problem with traditional rollers is they don't go deep enough if you have one of these scar tissue issues - as i think you do. So what i did was made my own homemade version. I took one of those long foam rollers and cut a 12-16" piece off the end. i then cut that horizontally so that i have to equal section with each having a round side and flat side (the flat side is what you need). I then place a tennis ball on the round part with the flat side down on a firm surface. what this does is props the tennis ball up so that when you lays on it or put it under your hammy it can really dig in. find the spots that hurt - and grind on them. spend as much time as it takes to make the pain go away...also you can move the out limb - like the lower leg when you do this - and this is the key because when you do this you are helping to break up that scar tissue. it won't magically go away over night, even though you will get immediate short term improvement. each day the tightness comes back. but over time it will gradually get better until one day you will notice it is gone.
i hope this helps you. i absolutely know the frustration you are going through because i am right there with you. i am so close to being injury free after 3 long years. i never went the surgery route but did try a chiro at one point with little success...because i was already doing all the things he did. this is where the smashwerx videos come in. just google the pain and smashwerx and you will get some drills you can do at home, right now. and they work!
finally i found a new exercise just this past week that really helped reduce the tension in my low back. sometimes you just have to try different things and will then find something that works. i had been doing rowing - which was working to loosen up the back. but one day i again over did it and it made it worse - so now i find that simple legs press machine is better for me because it is easier to control the speed. i use no weight at first and simply do a slow, deep leg press. x 10
i added just a little weight after a while (i think it was 2 50's, but have since cut that back to 2 25's - it is just enough to add a little pressure. this has worked great for the back tightness which then helps the hip. it is all connected. so keep trying different exercises. i believe the solution is in exercises = movement = and reducing the scar tissue from the original injury.