Is it normal to still feel the rods in your back several months after scoliosis surgery?

It can be. You had a spine deformity corrected to some degree with a fusion done to hold the correction with the instrumentation holding and creating this correction until the fusion is complete. You are adjusting to this correction and surgery and it is normal to feel that way. Unless your are very skinny, the rods are usually not felt unless one breaks or becomes loose.
Maybe. Most patients do not "feel" the rods in their back after scoliosis surgery, but often a sensation of stiffness is related. In thin patients, I have seen cases where the hardware can be palpated due to less soft tissue thickness over the surgical site.