Tendonitis is most likely the cause. I have this in several places including the groin area and it hurts when the pain strikes. Yes, pressure on the area does seem to quite it down. Taking an anti-inflammatory med may help. I take Limbrel and it has helped me (Limbrel is in the class of a medical food by prescription only). Doctors have only diagnosed me as having "inflammation" and not said it was arthritis. Some medications can cause tendonitis. In my case I believe Actonel was the cause (I have tendonitis in feet, knees, groin, hips, lower back, shoulders, arms, wrists, hands, all fingers/thumbs..just had surgery on one thumb).