Just sounds like your bars are too low in relation to your saddle height to me - ie. most probably because you have long legs in relation to your torso length. This isnt anythgin to do with getting used to a low position - I have this problem on nearly all my bikes, because the head tube and steerer is never long enough for me on a man's bike, as my legs are long and torso is short in comparison to a man of the same height, so I have to put my saddle very high in relation to the bar height. I don't have a problem with flexibility and have ridden thus far with a very low position, so low, in fact that it is commented on my most who see me, but I have had no choice due to the limitations of the second hand bikes I ride - most simply don't fit my proportions. It does put a lot of weight on arms and also on soft tissue in the saddle contact area so it's obviously far from ideal. If the steerer is cut too low and/or the head tube is too short though, there isn't much you can do, if you're already at the limit of the steerer height, except try an adjustable stem or get one with a sharper upward angle on it which will look odd and may effect the steering but which is the only thing that will help. Next time you get a bike, if you can afford it go custom made, or try to find one with a longer head tube and thus a longer steerer (the fame angles will also be different) - this will restrict your choice of bike unless you go custom though.