What kind of doctor do I see to check if I have 'back mice'?

Hello, I have had 3 back surgeries and still in pain. I have Knots on my lower back on the side that hurts. After many MRI, CT, injections and nothing worksI have been researching theses knots on my back. A pain management dr told me that my cluneal nerves were inflamed . So she injected them . It did work but came back. But there is a underlying cause for them being irritated. I have like a cluster of knots under the skin on that side. I am thinking it is back mice. What kind of dr do I see