Last 3 months I have been having a strange tight heavy feeling in left lower abdomen sometimes sharp I do a lot of lifting, my urine/stools are fine.

Possible Hernia. Given your history of heavy lifting you may want to be seen for a possible hernia. Don't delay as some hernias can be dangerous.
Here are some... I do agree to Dr. Willson's opinion with left inguinal hernia as the focus of attention, but still, go to be checked as advised. How to make the process of care as fruitful as possible? Follow instructions in articles listed in http://www.formefirst.com/onDealSickness.html; thereby you gain insight oh how to work well with doctors for right diagnosis and care.