What you are experiencing is common. I had the same thing, plus I felt like my lymph nodes were bruised. If you have ever seen an intubation (kinda gross) that is where they grip your head to get the tube in. Plus, they nicked my epiglottis a bit so I ended up having a white thing there for a few days while it healed.
Definitely keep using your spriometer (or whatever breathing exercises) and you will slowly get better! Congrats on the banding!!!