Ganglion cyst surgery 2/2015. Still have quite a bit of pain in base of thumb (site surgery) it's been 5 months. Why still pain?

Hand surgeon. This question is best answered by your surgeon who performed the procedure during which superficial nerves were probably disturbed and are very slow to grow back. I'm sure the surgeon will want to examine your hand if you're having so much discomfort 5 months later.