Deep muscle pain in the buttocks could be piriformis syndrome or sciatica, or could simply be a muscle spasm from exercise, states WebMD. Piriformis syndrome is a condition in which the piriformis muscle (a thin muscle located in the buttock) presses on the sciatic nerve.
Sciatica is a issue cause by trauma to the sciatic nerve. This trauma can cause pain leading from the lower back to the buttocks and down to the leg. Both of these conditions rarely require surgery and are usually treated with stretches and massages, according to WebMD. A muscle spasm usually resolves on its own.