My girlfriends body is always sore. she is achey and crampy all the time. she is only 22. what could this be?

Fibromyalgia?: Especially if she also notices she does not feel rested when waking in the morning, fibromyalgia is a consideration. It's a disease of the brain cells causing them to modulate body sensations abnormally. A physician can make the call. The treatment is often low doses of two types of antidepressant plus as intensive an aerobic fitness program as is tolerable. Just one possibility.

Suggest muscular: Can't be completely clear but suggest this is a muscular reason. If this is widespread myofascial pain, this would suggest fibromyalgia which is a chronic pain syndrome. There may be other reasons and she would benefit from an evaluation. Depending on the diagnosis there ae a variety of therapies available.