In the last year had lots of mri, cat scan, xray ultrasounds of my chest & stomach & my head & knee how much of a risk do i have from getting cancer?

Minimal: First, MRI and ultrasound do not increase risk of cancer. These do not involve exposure to any radiation. CT imaging and to a lesser extent plain x-rays carry a very small risk, which might become significant to an individual if tests are repeated frequently over many years. It is estimated that a single CT of the abdomen might increase cancer risk by 0.05%.