My stomach is very painful below the belly button it's been going on for awhile what can cause the very pain?

Many possibilities: Could be urine or pelvic infection, bowel or muscle or even early pregnancy problem. Will need to see a doctor (suggest GP) for examination and maybe testing. Please do a urine pregnancy test if sexually active within the last 4 weeks and seek urgent medical attention if positive, otherwise see GP for further assessment. All the best.

Belly pain : There can be various possibilities for your symptoms like urine infection , pelvic infection , gastroenteritis, intestinal problems , ovarian cyst, pregnancy , fibroid etc. Please take painkiller like paracetamol and see your doctor immediately.