After I gave birth to my second child, every one or two months I will have a fever. Is this normal? My second child now is 1 year old.

Fever. I dont believe the fever has any relationship with your pregnancy and delivery.You should check with your doctor and see him/her when you are running fever.
Insufficient info. Recurrent fevers are a concern. There are a number of things that could be causing them, but without a more complete evaluation it's impossible to tell what's going on. My advice is to take your temperature and record it when you feel feverish. Don't trust just "feeling hot". Use a thermometer. And see your doctor when you have fever. During an episode is the best time to investigate the problem.