I have been experiencing severe spasms in my upper stomach (at least that's where I think it is). There is no pain. But it mostly happens only when I am laying down. I have been experiencing some spasms sitting up, but mostly laying down, and mostly on my side. What could be causing this. It grips me so hard at times that I have to shout out (not like Tourette's). Can someone please advise what this could possibly be?