First day of period, and i'm having some pain in the upper left of my abdomen, feels sore. could possibly be from wearing high waist shorts. normal?

Uncertain: Unless you always have this pain every month with your cycle then we can not consider pain normal. I would not think the type of shorts you are wearing would cause pain but you could change clothing to see if that helps. Abdominal pain is complex issue with many possible causes. An evaluation by a doctor is needed to help narrow down the cause.