Its possible you have 2 main issues:
1)Your glutes are not firing
2)You physical posture and alignment are off, with weak transverse abdominus and maybe even lumbar multifidi
Weak or non-functional glutes leave the hip too far forward after each stride when you run, resulting in the iliopsoas and adductors and ITB taking the brunt of the landing impact, which would have been dispersed had the gluteus medius been firing to stabilise the hip laterally, and if the gluteus maximus been active to facilitate hip extension rearwards. Some heel-striking would also be prevalent on that same leg as a result of glutes not firing.
Glutes usually don't activate in runners who have less than ideal posture, which result firstly in the back and hamstrings taking over the job of stabilising the hip instead of the butt. Another cause lies in runners who straighten their legs fully in front and behind with each stride, thus calling upon the hip flexors and quadriceps to bring the hip forwards and to stabilise each step. Over time, overdeveloped hip flexors and quads will bring the pelvis to an excessive anterior tilt which would impede the activation of the glutes.
Poor posture also results from weak/inactive transverse abdominus (TVA) which allows the spine to curve abnormally. This can create a tilted pelvis which shortens one side of the groin and lengthens the other. This can result in symptoms like low back pain, hamstring tightness that do not get better with stretching, even knee and achilles issues.
You may need to work on strengthening your glutes and core (esp TVA), stretching out the hip flexors and quads, and finding an aligned posture from head to shoulders to hips to ball of foot as one straight line. If your head is out of alignment for example, it usually tilts more to one side or the other and this can cause shoulder and groin tightness on the side that it leans towards. Check your normal posture with a mirror and see if anything is too far forward or backward.