I currently have a sinus infection and my upper teeth really hurt more so on my left than right- is this all sinus related?

Very Likely: The maxillary teeth are in close proximity to the maxillary sinuses, they can be affected by a sinus infection and the opposite is true, after your sinus infection heals, your teeth should feel fine, if not time to see your dentist.

Talk to your MD.: It is rare for many teeth to "act up" at the same time (unless traumatic injury or massive decay) did you physician recommend a decongestant? If so, often that will reduce the sinus pressure, thereby reducing the pressure on the roots of the upper back teeth and reducing their discomfort. Once the sinus pressure and infection are gone, if your teeth still hurt, see your dentist.

Most Likely: The roots of upper back teeth are very close to the sinus floor, which often shapes itself around them. So when the sinus floor is irritated, as in a sinus infection, the teeth become sore and sensitive, too. They may even be achy, like yours. The difference in pain left vs. Right could be due to many reasons. Ultimately, you need to cure the sinus infection to stop the tooth pain. Good luck!