Af 7days late. Neg tests I am very bloated, crampy, sore lower back and pelvic pressure. Can be pregnant even though im testing negative?

Urine test? If you did a home urine pregnancy test i believe it takes two weeks from conceptionton show positive. (collegues feel free to correct the time line if needed) prior to that a blood test is needed for accuracy. If symptoms persist after a definative negative test, the symptoms are more likely some other gyn/gi/muscle issue that your doctor can work through with you.
Unlikely. More probable cause would be an ovarian cyst which can cause all those symptoms. An evaluation by your doctor can help answer the question.