Feeling like something crawling or rolling under skin

My mother feels like something is crawling or moving under her skin. It is located on the left side of her thigh. It is not painful, but there is pain when pressure is applied as when resting on her left side. She also has some hip pain. It happens mostly at night. Never when walking or sitting. She said it feels like a small hamster moving under the skin or large bubble. I'm concerned.