If your nodes are sore it probably is just an infection, especially if this happened all of a sudden. If they are still sore after two weeks and/or if they continue to get larger you should then seek medical attention again. At this point you need to tell your doctor you have been watching them and they are getting worse.
I have been having a similiar issue with the lymph nodes behind the ear on the boney part as well. It started off swollen and dore and I had gone to my ENT who put me on anitbiotics but he told me it was a cyst that I was born with that was infected. When I went back he said they were swollen lymph nodes. Although they aren't sore anymore they are still a little swollen which could be because I keep touching them. Apprentily lymph nodes are very sensative to touch and the more you play with them, the more they swell. The ENT wants me to go to a dermatologist because I have this wierd rash in that area. I am going on tuesday. I have had this for a couple of weeks now and I too am concerned.
I would get a second opion if I were you. It could be any thing from and infection to lymphoma. When you get it checked again I make sure you are clear in your understanding about what is going on. It really makes me mad when the doctors just kind of blow you off. I know someone I work with her daughter had a similar case and they did a biopsy of the lymph node. Turned out she just had an infection (she had it for 6 months). They put her on some antibiotics and with in 2 weeks it was gone. Good luck!!!