What does it mean when you already have spinal problems, but theres more pain, and my big toe is numb?

Nerve root pain: Often a pinched nerve in the back will present with numbness or pain where the nerve goes and at time be completely unassociated with back pain. In the case of a numb great toe it is the L4 nerve root. A non spinal nerve numbness can come from the medial plantar nerve (like in a tarsal tunnel) or the superficial peroneal nerve tar.

Means its time: To see the doctor. That numb big toe may be a direct result of the low back pain and you don't want it getting worse.