Don't worry, yeah that's what basically a lactic acid buildup is. It's basically the body's immediate response to try to "fix" your muscle tissue, figuring the exertion was overall damage. It can hurt like hell and also make things stiff to the point that you can barely move.
Now the good news. After your first serious workout (most especially if you haven't done it in awhile), it gets far less intense the next time. The times after that, you'll hardly feel it at all. You will just feel specific muscles being sore after you work on them according to your routine. You will have virtually no problem getting up and moving your arms to turn a doorhandle, etc, on the next few workouts.
So persevere! But, don't work out now again until all the soreness goes away. It could be 4-5 days after the first session. On my first session a few weeks back I thought I wasn't going to be able to walk/move/bend/unzip my fly. But, after 5 days everything was peachy keen and I continued my regime, doing larger weights each time.
So again no worries, in short
