this past weekend me and my dad shot my new double barrel that i bought at a gun show. turns out it shoots great and i love it. but we tried to pull both triggers at the same time just for the heck of it, and it wouldnt let us pull both triggers at the same time. so eventually we just ended up pulling one trigger then right after that pull the other. so question is do only some double barrels let you pull both triggers at once?

this is a pic of the gun

Many double barrel guns with double triggers will allow you to fire both barrels at once, however, the receiver is NOT designed to withstand this force, and it WILL increase the wear on your gun, and I've even heard of barrel lug failures caused by this practice.

so its kinda a good thing that im not able to do this

It also hurts the gun as much as it hurts you. My double had a bent sear and started shooting both barrels during last year's turkey season. Of course I had to try it again just to see what the problem was. Trust me when I say 4 ounces with max powder will leave a mark. A dozen times later I gave up and my shoulder went purple and stayed that way for a long time.