Well, it depends... 1. what kind of massage therapy are you planning on doing? Some energy work, craniosacral, etc. is a lot of touching and holding, not as physical. The kind I do, neuromuscular therapy, is more physical work. I get deep at times, push, pull, stretch, and if the people are large, it can be difficult. Of course you must always use proper body mechanics, and do the stretches and exercises that you advise for your clients. And make sure your table, chair, etc. is at the right height for you.
Do you have an actual injury or just pain, etc? The things you should learn in school will teach you some reasons for the back pain, such as poor posture, the structural imbablances which can cause pain and you can do something about.
I actually have a "bad back" also...a herniated disc L5-S1, and as long as I take care of my body, it is OK. Lots of stretches of the HIP FLEXORS (anterior) to keep them from overpowering the posterior muscles and causing an imabalance there. Actually, you would be surprised how much back pain comes from
RELATIVELY weak butt muscles.
I also have a bad neck! I have been in a couple car wrecks with whiplash. That is what gives me the most problems, tightening up when I work. But if you have someone who can work on you, and again, keep yourself in shape, you can be OK
Right now my hands and wrists are sore...not sure if from overwork or improper positioning while doing tripgger point therapy... so working on myself and stretch, taking nutrients that are supposed to help joint function, etc.
So....yes, it can be hard on you, but if you take care of yourself you can do it