A manometry does often not show up any problem with the upper sphincter as the manometry tube has opened the sphincter and most are not sensitive to show dysfunctions. I had a manometry in December when I was having really high pressures at 196 and 207, when your normal pressure is around 60, the manometry said full coordinated opening - utter rubbish a barium swallow 1 week later showed a full crycopharyngeal dysfunction.
A barium swallow, or better a Videofluroscopy will show the swallowing of your whole mouth, pharynx, and sphincter, and any problems related to it - and it's a breeze to do, drink some chalky liquid while being x rayed.
I would ask for a Videofluroscopy this is the same as a barium swallow but with food, and a speech therapist will spot any abnormalities.
Hope that this helps