It's been nine days that i'm missing my period.. i get some burning sensation in my stomach.. i've taken 2 pregnancy test & they come out negative.

See below: If you did the test correctly and it was negative at 9 days after a missed period, you are unlikely to be pregnant. You may wish to repeat the test in 3-4 days. Use first morning urine and follow the instructions for the test carefully. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex. Get HPV vaccine.