I have been working out at a certified gym and I get some sore back from swings (especially the days I am doing 8 sets of 10). I mentioned this to may trainer and I used a roller on my back that day. It really helped out. Also, in talking with her, I am most likely getting pain because I am working my entire core and it isn't very strong.
I second the suggestion of finding a certified trainer. It may be expensive, but they will correct your form, make sure you are doing them right, be available for questions, be able to modify exercises if needed, etc.
I don't think kettlebells are any more dangerous than other exercises, though, as someone implied. If you do not use the proper form in anything, your are opening yourself up for injury.
| Pounds lost: 6.8