Are high heels *really* that bad for you?

95% of the times I'm a flip flops or sneakers type of girl, unfortunately, my boss would fire me if I tried to get away with that at work. My flats that I use as work shoes are full of holes and no longer acceptable (I'm working to find another pair but it's hard to go shoe shopping when she schedules you for 9 days in a row, plus I don't really feel like spending the money on a pair, I'd rather use it for something I'd enjoy rather than work shoes). So for the last 2 or 3 weeks I've been wearing plain black pumps but I've heard this sort of thing is hell for your feet, your knees, your hips, your back, your whatever.

They're high quality designer pumps and I usually can get away with taking them off once I actually *get* to my chair, but I'm still walking around in them quite as bit.

Since I mostly wear normal flats, will the little time that I do run around in heels not really make much of a difference? I mean, I don't want to do this now and then screw my self when I'm like 50 with back or feet problems.

For the record, it's probably like 2 miles total that I'm walking in the heels 5 days a week.