See first of all you didn't mention your profession and any history of pain but according to me you are suffering from rotator cuff injury, due to that nothing is found in x-ray because muscular problems doesn't refect in x-rays. So according to me you should consult a Physiotherapist as soon as possible because its already very chronic problem.

Its most probably muscle imbalance of scapular muscles because of which there might be taught bands within the scapular muscles. You must see a hood physiotherapist for your problem. This issue is very well curable and u will have relief for life time

Please go through with physical examination with a good Physio