It sound's like gas to me..but you need to go see your doctor just in case it's not gas..
You just need to go to your doctor and have him/her to check you out..that can be many of things,and we just don't know what it could be..and have you put a cold pack on it to help with the pain?try that see what it does..
I just wouldn't use lemon juice,because you never know what will happen. You need to call your doctor and ask him the question's,because you may get the answer yes and it hurts your liver...your liver is very sensitive..