Hello and hope you are doing well.
The pain could be TMJ arthritis. It could also be due to other causes like temporal arteritis, tooth infections, tooth abscess or periodontal disease. The other common causes for pain are cerumen (ear wax) impaction, otitis externa and other infections of the ear. You will need to consult your primary care physician for further evaluation, who may then refer you to an ENT specialist.
Hope this helped and do keep us posted.
Since you say the pain started in your jaw a couple of months ago and now you feel it in your ear, I'm thinking it could be TMJ - which is a disorder of the jaw joint. It can cause many symptoms, including ear or jaw pain, as well as headaches, etc.
Do you ever catch yourself clenching your jaw? Does your jaw crack or catch when you try to open it wide, such as with yawning?
I would suggest starting with your family doctor - just to rule out any infection in the ear, however, if it is TMJ, the best person to treat it would be yoru dentist or oral surgeon.
Best of luck!