Having a slight heart murmur as a child mean I will have heart problems in the future?

Not necessarily. Many children have murmurs. And many of those murmurs are "innocent", meaning they are not related to an actual problem with the heart. On the other hand, murmurs can be a sign of a problem. Please discuss this issue with your physician to determine your specific level of risk.
No. If i listen to a kid often enough in his or her childhood i will hear a slight murmur in all of them. Murmurs reflect the sounds made by blood flow and or the dynamic action of the heart. Although they can suggest structural abnormalities in some, most are innocent.(not indicative of disease) most simple murmurs have nothing to do with later risk.
Heart murmur. Minor heart murmurs usually don't develop into problems in the future. They do bear observation and follow up however to be sure.