1 or 2 raised hives on the body every day (they look like a semi-sphere, red, itchy, and disappeared in 20 minutes) is it serious? About 10 month

Probably not. If the problem is so temporary , it is unlikely to be serious. If it starts to bother you more often or becomes more severe, see your doctor. Another approach would be to take an antihistamine every day to see if it would stop the hives even though i don't really think it is necessary.