It is unlikely that the symptoms you describe truly are due to chronic sinus problems. One seldom experiences weight loss and that raises suspicion that the headache and dizziness are caused by something other than sinus problems. Even if you do have sinus disease, the left arm numbness and tingling would almost certainly be unrelated to it. The first step should be to seek physician confirmation that you have significant sinus disease.
The second step, and you can address both your concerns with your doctor at the same time, should be to determine the cause of the numbness and tingling. Causes of that can range from heart disease, to hyperventilation, to peripheral nerve disease that is not related to the spinal cord. Please discuss this with your doctor.
Look up the full symtoms of TMJ, Sound like this!