Iride01 

Depends. If you ride your bike in off road terrain and are constantly yanking on the bars to get weight off the front wheel to go over obstacles then probably not the bar. I suppose if you constantly hop curbs and road furniture, then maybe it's not even a problem on the paved road.

However simply changing to another bar type might not solve the issue or it might create another issue or two for the one solved. Bikes designed for flat bars are going to have their geometry figured out for your hands being at a certain reach from the saddle. That is not going to be the same as what you'll have with a drop bar or most any other bars. So your bike may no longer fit you with a simple bar change.

If it were me, I would probably try some of those old style swept back bars that they use to put on 3 speed english racers or old roadsters from the 1950's. Then you might still be able to use your current shifters and brake levers. Don't go too wide either. That just braces you up and puts most of the forces from bumps and stuff into your arms and shoulders.

All just IMO. I'm not an expert, these are just things that I perceive as the reasons for some of my experiences in the past.