I am experiencing pain in the lower back and in the rear of my neck. Perhaps my bicycle frame is too small, however i am not sure this is only problem - see street bikes riders ride facing down a lot like in swimming you keep your head down, i cannot do that, i tend to look ahead of me 100% of the time (sometimes i ride on sidewalks, also there's holes in the road i want to spot to ride around) it just feels natural to me to know where i am going. I currently have mountain bike, but handle bars are flat, i was thinking of installing medium hi-rise handle bars but it might look stupid plus not sure how it will affect steering. Currently i am in the market for new light weight bicycle 15 pounds, so road bicycle is the number one choice, i obviously don't need a drop down handle bars just straight or medium hi-rise. Need more info how to select correct size frame also and any advice on the situation with the pain i get after several hour ride. My ride style is commuting, i am doing food delivery on a bicycle, i don't care much about, top speed and aerodynamics, usually i ride for 8 hours a day.