What can you do for a painful shoulder - likely rotator cuff? i don't know how i injured it.

Try ice/ antiinflamm: Intially, would suggest relative rest (no heavy work or lifting, stop weight lifting, sports using the shoulder), ice for 15-20 minutes nightly the entire shoulder area with flat flexible soft ice pack. Alternate with heat application, or topical like aspercreme, icy-hot.... If tolerated, may try two advil (ibuprofen) or one to two alleve daily with food. If problem persists more than 10 days, see doc.

Diagnosis?: Shoulder pain can have many sources and we need to first establish the cause for your shoulder pain. If rest and over the counter options have not helped see a doctor for an evaluation. Learn more about shoulder pain here: http://theshouldercenter.Com/shoulder-pain.Htm.