I have a heaviness in the left lower abdomen that is constant and dull in nature. However, it is severely sharp when I make any sort of movement. I've had it for the past three hours possible causes?

Many possibilities. abdominal wall, colon, small bowel, ovary, etc. colon: constipation/distention. small bowel: distention, ? a kink, ovary: follicle which has not yet ruptured to shed egg. All these likely temporary, likely to resolve, but difficult to know even in person & impossible to judge from a long distance via text. Study abdominal anatomy on the internet, self-exam, learn, consider medical help.
Muscular? A dull discomfort in the left lower abdomen that becomes severely sharp with movement may be muscular in nature. If you lie on your back and lift your feet several inches off the bed you will be tensing your muscles. If you then press in firmly in that area and it is tender suggests muscle wall strain. But if it's only tender with muscles relaxed pain more likely intra-abdominal> See Dr. ASAP.