Can a bad tooth give me p[ain in my left side of my back and stomach, I have had urine and blood tests come back normal,I am having a scan on Thursday to see if there is anything to be seen there?

A bad tooth is fully capable of killing you via a serious blood infection that can settle into the heart if left untreated long enough. If you doubt that... people with certain minor heart defects have to take oral antibiotics prior to any NORMAL dental work as a precaution.

But as far as stomach ache and back ache? Can't answer that.

Smoothy is right. An infected tooth can cause serious problems like heart attack, blindness, stroke and death. I'd suggest you see your dentist very soon!