sudden onset of lump with pain and tenderness most likely due to some trauma or infection .
for the pain you may take paracetamol
tab. If you are running temp you may start on antibiotics like amoxycillin
combination 3 times a day
CLINICAL EXAMINATION AND INVESTIGATIONS LIKE CHEST X-RAY ,USG WILL SETTELE THE ISSUE .
Hope with proper treatment you will be all right soon .