What Causes Chronic Pain In Coccyx?

My tailbone usually hurts as if it is a severe charlie horse. Then the pain goes into my left buttucks. Naproxen twice a day chiropractic visit today and the shooting pain to the buttucks is subsiding, but the tailbone is sore and hurts when I cough, move in a wrong way, bend, squat, walk, lift heavy items and get up.