I think you need to offer more information. And I have some doubts that wider bars will correct your position, though it is possible if your bars are extremely narrow relative to your body. I suggest you consult with some more "experts". It's normal to have some discomfort when riding farther than usual. If your shoulders hurt try relaxing your arms and bending your elbows.
Replacing the handlebar with a wider one will probably require replacing the cable housings as well as the cables.
Al