hiii you mite be suffering from sumthin called as urticaria. it's an allergic reaction to anything of the body. you need to observe if it is associated with any food item,any dust,any medicines,hot or cold exposures, following contact with any substance, use of anything new etc. we can giv u an antiallergic medicine to control it. see a dermatologist who will do a few blood tests an try to find the exact cause.