I sometimes wake up at night choking.could it be acid reflux?

Possible: Yes, acid reflux is possible, but not the only cause. Another fairly common one is sleep apnea. More history is needed at this time, i'd see your regular doc.

GERD: Also called gastroesophageal reflux disease. Common symptoms such as heartburn, bloating and sour or bitter-tasting acid backing up into your throat or mouth are the key to the diagnosis of acid reflux disease. The good news is a treatable condition. Rec.: see your pcp for diagnosis and treatment.