Hi Vee

It is probably just a strain caused by the rotation movement when you were driving. Back injuries are pretty common among golfers, even the elite, who train hard to prevent them, and so it's not all that uncommon that someone playing for the first time in months would suddenly experience some pain - if you think about it, the swing involves a huge acceleration when the downswing starts, and the back really does take some strain.

As far as the future goes, the first thing is to make absolutely sure that whatever muscle damage, or strains were there are completely healed. I know that the pain has gone away, but perhaps give it a few more days of rest before you swing hard again. Then, there are some exercises that can be done - I'm not sure if you have access to a gym. if you do, check out the following site, where you can see some exercises to strengthen the back:

http://www.health24.co.za/fitness/Zone_in_on/16-472-483.asp

I think that perhaps more important is to warm up before hitting - you can do this by stretching, but also by taking a few easy swings, just to loosen up the back before you play. If you suddenly swing hard with a 'cold' back, it's a recipe for disaster. Here's a website with some stretches

http://www.health24.co.za/fitness/shape_up_for_summer/16-173-178.asp

Lastly, remember that of all the shots, the drive is most strenuous for the back. What happens a range is that you often hit about 30 balls at a rate of more than a ball a minute - this is really quite stressful, compared to golf where you can go for about 5 minutes between shots. So, at the range, even taking your time may help

Good luck