What can cause sharp stabbing pain in my lower left abdomen worse while standing or sitting could h pylori cause these horrible pains?

Left lower abd: H pylori infests the upper gi tract ( stomach)and not the lower. Sharp,stabbing pains there may be gas buildup in the colon or simple colonic spasms. Pathology involving the left ovarian or pelvic organs are other possibilities. If frequent symptoms persist, see your physician for examination and appropriate tests and/ or referral to a gastroenterologist or gynecologist may be ordered.