Hello,
What you are having looks like dermatographism. The other possibility is of hives. Dermatographism can be caused by stress, tight or abrasive clothing, watches, glasses, energetic kissing, heat, cold, anxiety or anything that causes stress to the skin. It can be treated by antihistamines or cromoglicate and sometimes steroids, as they prevent the histamine from causing the reaction. But as the underlying cause of dermographism is not known, it can last for many years without relief.
I hope it helps. Take care and regards.