I have a problem keeping my heart rate under 150 when I'm trying to do an aerobic workout even when I'm going really slow. Target is 127. What to do?

Heart rate. Sounds as though you need to work with an exercise physiologist and have a consulting cardiologist ensure that you have no underlying cardiac issues. So much depends on your age, level of fitness, bmi and so forth.
Your starting point? First, what is your age? 220-age roughly = target hr. Remember, this is a rough guide..Sustained hr at about 85%o of target is ideal for aerobic exercises etc.. Also, if starting hr is 60, then 150 is relatively fast. If resting at 95, then 150 is not so bad. Hr rises more rapidly when you are not well conditioned. If u feel ok, i would not be too concerned. Consult doc if u r concerned. Good luck.