I Was Helping A Friend With Landscaping Work And I

I was helping a friend with landscaping work and I think I strained the muscle on my right arm just above the wrist but below the elbow ..on the upper surface.... the forearm I guess.
There is some swelling but I've been applying a cold compress periodically and have it wrapped with a tensor bandage. The project is done; so, now I will rest it. Do I have a muscle strain? How long will it last?
Am I treating it correctly?