Rest is often the best thing for shoulder pain from tendonitis but remember that prolonged resting of the joint could cause frozen shoulder. (2:14, 15 ) (7:3)
Shoulder problems are most often first treated with RICE (Rest, Ice, Compression, and Elevation): (7:2)
Rest. Don’t use the shoulder for 48 hours.
Ice. Put an ice pack on the injured area for 20 minutes, four to eight times per day. Use a cold pack, ice bag, or a plastic bag filled with crushed ice wrapped in a towel.
Compression. Put even pressure (compression) on the painful area to help reduce the swelling. A wrap or bandage will help hold the shoulder in place.
Elevation. Keep the injured area above the level of the heart. A pillow under the shoulder will help keep it up.
Non-Steroidal anti-inflammatory patches are available which can be applied directly to the painful area. Ask your doctor or pharmacist about these patches. (9:1)