Esophageal Motility and Lap Band Surgery

I am waiting surgical review. I have just been told that I need to have a Esophageal Manometry done. What could the problem be? I do not have any problems swallowing. And, I was also told that I have a hiatal hernia. I have not had any problems. Didn't know I had one. Will this cause me not to be able to have the lap band surgery?