<s>[INST] Hi, may I answer your health queries right now ?  Please type your query here...Hello, I am a 34 y/0 female 5'7 in height, 200lbs.  When lying flat on my back in bed overnight, I always wake up with extremely bad chest pains that eventually subside when I sit up.  It takes about 10-15mins to go away.  What may possibly be going on because I know this isn't normal! [/INST] Hi welcome to the health care magic It is difficult to predict exact cause without examination but it could be acid reflux induce chest pain as happen in lying down position ... If acid reflux and acidity history present than omeprazole prescribed for that Your work up done as follow... -Auscultation -x ray chest -EKG According to cause specific treatment given If no specific  cause found (including abdominal causes ) than muscular pain might be the reason Hence with keeping these in mind consult nearby physician or pulmonologoist for examination and further work up accordingly Take care </s>