Tightness near stomach and headache after EGD

A number of hours after an EGD, I started to get a migraine headache which did not go away until the following day.  Afterwards, I had a strange feeling as if a headache still lingered but was so slight it was almost not noticeable.  I also noticed there was some minor tightness around my stomach area (my left side if facing me).  Both symptoms have not gone away after 5 days since I've taken the EGD.  I was under very mild sedation, so I was told with Propofol and when I mentioned I had a migraine headache the day after the procedure, I was told it was probably coincidental and that someone looked up the side effects for Propofol and migraine headache was supposedly not a side effect.  However, after researching the headache side effect myself noticed it was (via drugs.com info sheet) but it was very rare.  Anyone have any information on this that might help point towards the cause?