Dr suspects disc herniation bc i have bad pain&numbness in my back,arms,&both legs.lately my hands/bottom of feet hurt to.could it be ra instead?

Not necessarily: We need to have a good history of when this pain started. I am assuming that your talking of your neck? If so, hand and leg numbness can be associated with it if there is a cord compression taking place by the disc. We call this a cervical myelopathy which could also trigger: balance problem, incontinence,etc. RA can also involve the joints but doesn't usually cause numbness in all limbs.

Disc: herniation in the neck or similar things is probably what it is. Doubt if it is RA. MRI and blood tests will help.

Less likely: While it is not impossible for RA to affect large joints like the back/spine, it is much more likely to affect the smaller joints such as in the fingers. However, in order for there to be a disc herniation affecting both your arms and legs it would have to be quite high up, in your upper back or neck. Testing, including CT/MRI imaging, and blood tests are needed. Work with your doctor to diagnose.