This infection may increase post-nasal drip. If you suspect that you have a sinus infection, you should see your physician to see if it needs antibiotic treatment. Chronic sinusitis occurs when sinus blockages persist, causing the lining of the sinuses to swell further.
Causes of Pain in Left Side Back. 1  Pregnancy: Back pain especially on the left side, is very common in pregnancy and happens for a few reasons. As the child develops in size, the uterus can pack torment delicate structures including nerves. 2  Kidney Infection: Kidney diseases can cause left side back pain.
If pain in the left shoulder is accompanied by pain in the chest, it is possible that one could be suffering from a heart attack. Stroke is also a concern with pain in the left shoulder. The Mayo Clinic's Stroke page states that numbness or pain on one side of the body accompanied by slurring words or blurred vision could be signs of a stroke.