Hi there babs.
The mastoid is a bony structure filled with air spaces inside your middle ear. The middle ear also houses the three little bones that modulate the sound that touches your eardrum. The mastoid is that part that you can palpate right behind your ear. Mastoiditis is inflammation of this structure as brought about by most commonly, an infection.
I agree with your decision to see an ENT specialist as he can examine your ears properly and thoroughly. Treatment would include antibiotics for several days and in severe or recurrent cases, the mastoids are removed surgically (mastoidectomy).
Hope this helps! Regards...
Hi, untreated middle ear infections or acute otitis media can lead to infection of mastoid process which is a part of temporal bone giving rise to bump behind ear. Usually treatment with antibiotics can cure this condition but resistant cases are treated with surgery.
“The diagnosis of mastoiditis is clinical—based on the medical history and physical examination. Imaging studies may provide additional information; the study of choice is the CT scan, which may show focal destruction of the bone or signs of an abscess (a pocket of infection”. Taken from http://en.wikipedia.org/wiki/Mastoiditis