I always hear about resting heart rates but what is a healthy heart rate when standing up to walk somewhere? my resting hr is around 65, but when i stand up i feel like my heart rate shoots up to like 120 (i havent actually been able to measure it?

You should actually measure it. A pulse oximeter is quite inexpensive and could put your concerns to rest. It probably doesn't jump as high as you think it does.

It would also be helpful to measure your blood pressure sitting & then standing, as some people's blood pressure drops significantly upon standing up causing a reflexive acceleration of the heart rate. Usually lightheadedness follows. This is the POTS which tends to occur in younger people.