Could also be a muscle or a nerve. The muscles in that area are controlled by the autonomous nervous system, they won't respond on command, so when pain occurs in these muscles, it cannot be controlled, only relaxed. If it is a nerve issue, then you would be in trouble... let's hope it's not a compressed nerve...
What happens if you use some betadine / povidon iodine on the area? When I have some pain or discomfort, I take a squeeze of betadine and massage it over the whole area. It helps to protect against infection, and the pain goes away in my case.