Hello,
You are experiencing pain on the face (L side) and back of the head while coughing. You recently had an 
ear infection. Presently, you cannot hear properly and have sounds in the ear. You are having symptoms of tinnitus. You should get 
audiometry test done to detect the degree of 
hearing loss. Hearing loss can be due to impacted ear wax in your auditory canal. Partial or complete rupture of the ear drum, infection (AOM / COM), etc.
Get clinically examined by an ENT, get required tests and investigations done. Your treatment  will depend on the pathology detected. When the pathology affects the 
trigeminal nerve which carries sensation from your face to your brain, you will experience excruciating pain on even touching your face. Get neurological examination and MRI done. Get evaluates so that treatment can be started. In the meantime, you can take 
acetaminophen or muscle relaxants for relief.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Nupur K., General & Family Physician