How should i treat my shoulder muscle injury for inflammation?

Ice and rest: Inflammation is best treated with anti-inflammatory medications like motrin. Take it around the clock for a week. Also, apply ice to the shoulder for an hour every night before you go to bed. Avoid any activity that causes pain. If it does not improve in 1-2 weeks see your doctor.

Tendonitis: Initial management could include things like avoidance of painful activities/positions, use of nsaids (aleve, advil), periodic application of ice, and gentle stretching. As symptoms improve, gradually resume activities. Should pain not resolve, or get worse, consult with a shoulder specialist.