I went to the er was diagnosed with pid i am married all the std results came back negative what could be the cause of it i am in severe pain they sent me antibiotics. they let me know that my fallopian tubes were swollen and one of them was dialated?

Most PID is caused by STDs, usually gonorrhea or chlamydia. Even with your negative STD test results, you should discuss with your husband whether he has had other partners. But not necessarily; some PID is due to non STD bacteria, like Haemophilus influenzae. Don't accuse him, but do have a senstive discussion. Antibiotic treatment usually is very effective; you'll get better soon. Good luck.