I have been having pain when I lay down every night for the past week centered behind my sternum. When I am on my back the pain is a 3 and when I am on my side or stomach the pain is a 6. The pain will increase each hour I am laying down. Sitting up will relieve the pain within 1 to 2 minutes and there is almost no pain during the day. No burning of bile or problems with gas or reflux.