Are deadlifts good for your back?

Absolutely, but only if done PROPERLY. Doing deadlifts the wrong way will put you out real fast. Start light (a weight that feels too easy) and slowly progress. Make sure to stretch and warm up for this lift too. Stretch again afterwards.

Yeah as long as you don't over do it with the amount of weight you use. And your not carrying to much fat on your frame. Also if you do them definitely get a weight lifting belt for support. hope that helped...God bless you !