What you explain could be a result of incorrect frame size, incorrect seat position or height, incorrect stem length or your handlebar being too low. It could be that all you may need to do is to raise your handlebar even further. A stem riser doesn't cost much, so it may be worth to try it.
My wrists and hands were getting numb on my flat bar, but it went away as soon as i swapped the bar with an FSA Metropolis bar and put Ergon grips on it.