So thing about an achilles injury, at least tendonitis, is that you can really over-treat it into some pretty bad pain. This is just what I have experienced.
I had an injury a while back. It flared up during a track workout in mid february, and it really wasnt that bad, but Id had this injury before and wanted to play it safe. I took 4 days off, then jogged a little bit, it felt fine. I was committed to a race and I felt fine jogging and doing strides so I continued with the race. Wore racing flats and felt ok. Ran the day after, could feel a little niggle but still felt fine. I got scared so I took another 4 days off. Came back and didnt feel much pain, but it didnt feel right.
This was the point where I kinda screwed myself. I should have stuck with easy jogging 10-15 min a day, eccentric heal drops, and some massage with foam roller. Instead I freaked out and really got intense with treatment. I THOUGHT I was in the right direction.
I came back to running about 24 days later and did not feel right. I was pissed because I knew I had taken some good time off and the original injury wasnt really that bad.
Everyday I was stretching, massaging, icing/heating, eccentric heal drops, and wearing a brace at night to keep the ligament from scrunching while asleep.
I basically started running 8-10 min a day easy and after a couple days the pain was so bad in the morning and I knew something was not right. When I had originally hurt the injury I was training hard and the pain was not this bad.
I basically read this really good, research based article below and it changed everything I though about achilles tendonitis.
http://www.runningwritings.com/2013/11/achilles-tendonitis-in-runners.html
Basically, it says that the only reliable methods to treating AT is rest, and eccentric heal exercises. Somethings may not help, but wont hurt. Other, will really make it worse. Ill just outline it briefly.
Do
Rest
Eccentric Heel Drops
massage
Sometimes helps, but wont hurt
Maybe ice after activity
Do not
Heat
Stretch
Sleep with a splint
Wont go into all the detail with the why not on those last 3 but I basically went from bad to good after following this plan. Ran 16 min one day.. Not really any pain at all. Started to feel some stiffness later into the evening (more than usual) Did all the treatment, woke up the next day and the AT was so tight. I usually had morning pain, but i was worse. Pain prob about a 6. It wore off as the day went on but still hurt.
It was that morning I came across the article above. I didnt stretch at all. I went to the stationary bike. I didnt heat or ice, I did eccentric heal drops in sets every 45 min till right before bed. Right before I went to sleep I massaged lightly with a foam roller and did NOT wear a brace or splint to sleep. I woke up the next morning and the pain was about 1, or less. That was my immediate first steps getting out of bed. After that I was sold on never doing any of things with an AT injury.
I feel like even though its a pretty strong tendon, the strongest in the body, its also a pretty sensitive tendon.
Good luck.