What Causes Backaches And Headaches Along With Bumps On Stomach And Thighs?

Often lower back aches---lately developed itchy bumps on stomach and thighs (really bad at night). Last week left work because of feeling lightheaded, nauseated, headache, fatigue,not feeling well at all. Still have bumps, tired and fatigued(morning and throughout the day) and headaches every day.