blazer 2008

I had to replace a rear wheel cyl. so I thought I would give everyone a look as well.The dr. fr. wheel spins and then gets tight,then normal and tight.I,m suspecting a warped rotor.The shoes still have some pad left.It drives fine with no pulling. Is my first jeep and 4x4 so I just wondering if I,m on the right track or is there some other underlying problem.If is rotor is it a pretty straight forward fix as in a normal car etc. Thank s