Came on Thursday night - it's on the top and on the inner side of my upper arm. Hurts like heck to move in certain positions especially across my body and upwards. Haven't done any exercise or anything that I think could've caused it. Otherwise well. Not sure if bears any relevance but currently approx 7 weeks pregnant I've put some ibuprofen gel on tonight which has taken edge off but definitely not got rid of it. It's driving me mad!