Being relatively new to riding a quality bicycle I did not expect numb palms and butt after riding a scant 5 miles. I ride a Globe Centrum Comp which I absolutely love & was fitted by the bike shop. I thought maybe the handlebars could be raised but the bike shop guy says the stem is fixed.

Granted I am 240 lbs and 5'8''. Will the comfort increase as I shrink in size? Or, do I need to modify the handlebar height for more comfort?