The "lump" that you're feeling is probably an enlarged lymph node. Your lymph nodes will swell when your body is fighting a virus or infection and yes, they can be quite painful. My guess is that you may have either a throat or ear infection that is causing both the pain and the swollen node.
However, I'm not a doctor, so please take this as strictly advice. Your best bet would be to have your parent, guardian or other trusted adult take you to teh doctor to be checked out. If you have difficulty talking to yoru parents or think maybe they won't believe you aren't feeling well, perhaps start with the nurse at school - have her check your throat and ear and then maybe she could talk to your parents for you about taking you to a doctor.
I hope you feel better soon!
I am also suffering from same kind of symtoms, in additions to this I also found some hard surface in my throat. I feel like I am having some heavy thing in my mouth, Sharp pains in throat and neck, this pain come from throat and goes to ear and head,
My belches are stopped at throat only sometimes. What this could be?