What should i do to relieve a sore shoulder?

Rest: I would first try a period of rest and avoid aggravation. Would advise starting a course of antiinflammatories and icing as needed. Can typically start with 800mg of Ibuprofen per day or 500mg of alleve twice a day which are rx strength. Gentle stretching also helpful and can google codman's exercises. Also work on rows and scapular strengthening. If not better in 3-4 wks seek attention.