I have been getting hives on and off for the past three days. They usually happen at night, but I have some this morning on my lower legs. They have shown up on my back, abdomen, chest, legs, and arms. I also have a stiff neck and stiff shoulder blades. I am wondering if I should see someone or keep taking diphenhydramine. I have never had this problem before. I am a 24 year old male pharmacy student.