Shoulder impingement

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Hello,

About 6 weeks ago after a weight lifting session, my right shoulder tightened up. I did not have any pain (havent had any). Just my shoulder and bicep felt very stiff (and inflammed).
After seeing physio and a few sports massages things improved. Both people checked movements and believed I have an impingement (If I mimic pushing a bar overhead, I can feel it tighten up. similar, but not so obvious, with raising arm to side). It feels okay, apart from the odd achey feeling, and a bit stiff when arm is raises to 90+ degrees.

My rhomboids seem to be quite tight, and I've had massages on them. And there is a stubborn knot. Its better now after two session last week, but I can still feel it. When I roll on it with a tennis ball, and then raise my arm, I dont get as much stiff feeling. But it does not last. Similar case with stretching. Im going to speak to my chiropractor on Monday and see what he thinks too.

Also worth noting I've had pelvis / leg length issues. I got my custom inner soles last week, after 2-3 months of lots of problems (lower back, SI joint, tightness, ahces...). Over pronation of my right foot, and left leg is 2-3mm shorter. So I've only just got this sorted, im still wearing them in. So at times my left leg was being pulled about, so I had a difference of 7mm (strained my psoas as well at one point).

I've been recommened to do external rotations and strengthening my back, suprising as I always have had an equal routine, and am quite strong at back work. I dont want to do direct back work yet, incase it causes inflammation of the biceps again (and I feel that it will).
I done two types of external rotations, internal rotations and a supraspinatus raise yesterday. Which felt okay (if anything, a little better).

Any further advice as to what might help, whether the tight rhomboids / alignment issues could be the cause, and any further action?

Thanks in advance

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Just to note. My chiropractor said that it seems to be an impingement of supraspinatus and bicep tendons (although hard to accurately tell). He said there is some stiffness, but I have decent range of movement. He said it was a bit worrying about the bicep inflammation and said it could have been a partial tear.

When he pressed on the supraspinatus muslce and bicep tendons, they felt quite tender. Not unbearable, but noticable.
Is worth noting that the inital injury came from overhead pressing followed by pull-ups. No pain, just stiffness afterwards and inflammation - espcially the bicep near the shoulder.

The discomfort at the moment is just a bit stiff and feels a little tight at the front of the shoulder. I sometimes get a sort of 'niggly' pain on the bicep tendon too. All of this on right side, but sometimes I get a little in my left side (rare). I cant sleep on my right side, otherwise it makes it worse. Sometimes my shoulder / arm stiffnes up and feels quite tight, even though im not going to the gym.

Chiropractor mentioned that an MRI is an option, if I want to do down that route. Which at the moment, I'd rather just find out whats wrong (MRI doesnt bother me, had one before), and find a decent physio who can help with things.

Had a bad day, so this pretty much put the icing on the cake. Some advice would really be appricated.