Thanks for posting your query.
Do you have some sort infection in scalp?
Do you have difficulty in hearing from right ear?
Do you have any boil in right ear?
Presence of tender lump behind may be an enlarged lymph node
is viral in origin and never causes enlarged lymph nodes behind the ear.
You should consult with internal medicine specialist/ surgeon and ENT surgeon.
You may also go for FNAC of the lump.
Dr. Mayank Bhargava