Wrong Question. Piriformis synd rarely goes away by itself.The question is 'What can be done to get rid of piriformis synd.?' Some people advocate stretching the piriformis muscle, but in my pain practice that rarely works.A simple, gentle osteopathic technique which you can be taught to do at home may help. I recommend seeing an osteopathic dr. trained in hands-on diagnosis & manipulation to get proper treatment.
Pyriformis syndrome. There are some excellent on line descriptions of the condition and necessary stretching exercises. Sitting on a tennis ball reproducing the pain helped my recovery. Rest from exercise is needed although you could try swimming or use of the ellipitical. Providing the diagnosis is correct -i would confer with a good physical therapist. Start your return to exercise slowly and stop if it recurs.