stiff jaw and found lump?

Hi all,

For the past five months I have been suffering from stiff jaw. I have been taking extra vitamins and found every other day it seems to ease up. Recently though it seems to just be constant. I went to the dr's and they prescribed me with Ibprufen  - have to take 400mg three times a day  for the next 3 weeks which is very annoying as they give me a  bad stomach. I got checked by the dentist and have been told my gums and wisdom teeth are fine. Noticed  lump at the back of my jaw on the same side that seems to be the most stiff. Bit worried to be honest. Dont wish to bother the dr again but the ibprufen doesnt seem to helping and the finding the lump has made me quite anxious
any advise would be seriously appreciated
cheers