so i finally got my own bike pump...and while i was trying to put air in my tires, i found it REALLY difficult. I couldn't pump it down enough and so i only got it to about 90-100psi...that's with putting my entire weight on the pump...is it suppose to be that hard? I know i'm putting the pump on the valve right, but i can't seem to be able to press it down enough after i get to about 70psi...can anyone give me any tips or tell me if i'm doing something wrong?