Question: Itchy scrotum, ect

Hi. well I guess then those are not my problem. What I am having a issue with is at night my scrotum, area near anus, knees, thighs, legs ect, basically allot of places on my body get very itchy. my private areas the worst . this seems to happen after sex allot but also on a hot day. at night the hotter it is the worse the itch. some days it's good others it's not. it's like I get these generalized body itch attacks a couple times a week, they last most of the night and onto the next day. I'm not sure if it's a skin type condition or a neurology issue. I also noticed that sometimes in the winter when I come in from the cold to a warm room sometimes I get a crazy whole body itch attack that lasts about 30 mintutes. during exercise sometimes tlo. something to do with going from cold to hot. Anyways any ideas ? Maybe an allergy or something? I recently started taking low dose verapamil (40mgx2) and nortriptyline (5mg) for migraine prevention but I had this itching problem before that so I don't think that's the cause. I had a bad itch attack last night and I still have it the next day! it is generally my private areas, hands, knees, legs, stomach, just about everywhere. it's not severe but it's pretty bothersome. Besides dry my skin looks fine I think.