What Causes Tightness In Throat Post Tonsillectomy?

I had a tonsillectomy about 2 and a half months ago and have felt a tightness more so on the right side of my palatoglossal arch and only recently noticed that the right side of my arch is considerably smaller than the left side. I am a classically trained singer and it makes it difficult to hit higher notes as well as speak words with a lot of nasal inflection. Are there any exercises or stretches that I can do to even out the size of the arch on my right side?