First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes. The symptoms you describe are non-specific, but could represent several underlying processes.
The numbness in the arm pit, would be most consistent with spine disease, possibly related to your arthritis and/or disc disease. The nerve root that serves the arm pit is T2 (2nd thoracic) and may be pinched in your neck/mid back. For this I would recommend a MRI of your cervical and thoracic spine. However, left arm pain/numbness in the setting of chest pain is often cardiac in origin, and I would stronlgy recommend that you follow-up with a cardiologist for any additional tests.
The other symptoms you describe, blurred vision, slurred speech, clogged feeling in head/ears, and clear nasal discharge, are difficult to place in one diagnosis. Since your symptoms developed over the last 3 months, It does not sound like a stroke (can cause vision problems and slurred speech) or basilar skull fracture (can cause a cerebrospinal fluid (CSF) leak). A tumor in the cerebro-pontine angle tumor or auditory canal tumor could cause the loss of hearing and clogged feeling. However, since that you have had a "normal" MRI these posibilities are very unlikely, (you should make sure your MRI was done with constrast, DWI, and flair sequences).
Occasionaly spontaneous CSF leaks occur and are associated with CSF fistulas that are generally located in the area called the ethmoid and occasionally around the ear area(when fluid leaks around the ear it can reach the nose through the eustacian tube). Sponatenous CSF leaks can be due to hydrocephalus (high pressure in the head, caused by tumors, meningitis, etc) or with normal pressure (fistula). The loss of CSF fluid may cause a headache disorder assocaited with postural headaches (the headache is worse with standing and improves with lying down). For this I would recommend a trip to the emergency room, or your local neurosurgeon to have the nasal discharge tested for CSF. CSF contains glucose and Beta-2 tranferin, that are not found in normal nasal discharges. If positive then a CT cisternography would need to be done to determine the site of the leak. Given the non-specific nature and complexity of your symptoms, I would definitely follow-up with a neurologist in the future. I hope this has been helpful.
I am trying to figure out what is going on with me. I have had pain and numbness in my arms, hands, legs and feet for quite a while now and it is only getting worse. I also have been extremely tired. The past few days I have not been able to do anything not even carry my daughter up the stairs. I had an EMG done and it came back normal and so did my blood work. My MRI showed a cyst on my brain but my neurologust said it is nothing to worry about b/c where it is located would affect my vision and hearing. Do you know anything about this type of cyst? He told me there is no name for it - obviuosly I am getting another opinion. Do you have any idea why I could be having these symptoms? Please help.