I've took 4 pregnancy tests and all are negative, 8 weeks after sex but i am experiencing back pain. any ideas what are the causes? also on cerelle

Many: There are many causes for back pain . Pregnancy is not even the first in the differential diagnosis. If you have had 4 negative pregnancy tests 8 weeks after sex you are not pregnant. Depending on where your back is hurting you could have kidney stones, gall badder disease, a bladder infection, a pinched nerve, a muscle strain, or several other things. Check with your PCP or an urgent care clinic.