A few more questions to ask is how long have you been riding this bike without being aero and have you only started having these issues when you tried riding the aerobars? If you have been riding this bike for any length of time and have never had any issues until now, it just may be the saddle or a flexibility issue. If it is a saddle problem, there are several saddles in the market that are made more for aero positions than riding upright. Saddles are an individual thing and everyone has their favorites that they swear by, including myself.

I ride 30-40 miles a day at a MUP and do 90% of the ride on aerobars. I never had any problems until I started losing more weight, especially from my butt. Then it got to the point that after 20 or so miles, I was ready to quit. I know it wasn't the fit because I get a Retul adjustment every six months and I had just had one done about a month before I changed saddles. I had been looking into ISM saddles but was a little leery in buying one because of the price. I went to my fitter and asked him about them and he highly recommended it. Several of my riding friends, as well as team members, ride on ISMs and all of them swear by them. I tried it and from the moment my butt hit the saddle, it was bliss. I have ridden 60 mile rides using the hoods, drops and aerobars and never had another issue with discomfort, pain or numbness since going with the ISM. I have the Prologue model which is made more for distance riding. After riding on an ISM, I will never ride another road bike without one.

If you determine that it is a saddle issue and adjusting your current saddle doesn't solve the issue, look into various saddles and find the one that is best for you and not one that is the best for someone else. However, you should use some of the testimonials and saddles mentioned here to get you started in your search. Good luck.