on my 98 dakota the brake pedal sticks down i have to pull it back with my foot to release the brakes

Generally, and I believe the 98 Dakota is no exception here, the master cylinder has an internal return spring that pushes the brake pedal back up when you release pressure on it.

Assuming that the master cylinder was actually replaced (and this is my assumption since you said it was) then the problem is elsewhere.

You should check the pedal pivot/hinge and the pedal to master cylinder linkage for binding or obstruction that made be keeping it from returning to it's normal position.

Beyond that, are you 100% the master was actually replace? Was it a new/rebuilt or a used unit? Did you do it yourself or was it done by a mechanic?

If you did it, you may want to pull the master cyl. and ensure that it's working normally. If a mechanic did the work, then in my opinion, it's substandard work as I consider a "brake repair" job to end up with functional brakes. It may be time to visit the shop and discuss the issue.