U r getting pain bcoz of grade 1 muscles strain or ligament sprain or there a r many reasons for pain.. u need to do some physical tests for perfect diagnosis.. 1) Crank test. 2) Anterior and posterior drawer test. 3) Clunk test. 4) Speed's test. 5) Sulcus test. 6) supraspinatus test. U should take physiotherapy treatment for 7 days to control further problam. Take ultra sound, IFT, Moist Hot pack. Need to do some exercises.. U will b better soon.. Thanks.. TC