II had severe pain in my right arm for apx. 12 hours. Now I have a severe bruise, apx. 8" in length, on the inside of my upper right arm. I haven't done anything out of the ordinary, no heavy lifting, exercise, etc., and I haven't injured the arm in any way. Is this condition serious? I am a 74 year old female, in good health, not overweight, no high blood pressure. Thank you.