Not to disagree with all that's been said, but to add... If you have upper motor neuron problems, you will have spasticity with hard muscles. I have mostly lower neuron (LMN) problems, with atrophy or wasting of muscles. Upper (UMN) causes pain from spasticity, and a lot of folks use Baclofen for that pain.
With later loss of muscle, the joints are held together with ligaments and tendons, which aren't intended to handle that stress, so there is often pain. Hip pain and shoulder pain are (just what I read about) the most likely to hurt.
Range of Motion exercise is really important to do. It can keep us from pain for a long time. If range of motion is good, the problem may be from one of these other causes of pain.