need advice and support

When I met with the personal trainer a few weeks ago it scared me from working out because I was told that if I'm not sore the next day from strength training, I didn't work out hard enough. If I do strength training 3-4 times a week am I supposed to live the rest of my life in pain and soreness? It doesn't make sense to me because if I can't even walk normal afterwards how am I supposed to maintain a normal lifestyle? I'm just extremely frustrated and stressed out trying to figure out how I'm going to fit a healthy amount of exercise into my new busy schedule as well as eat healthy. Please any suggestions are welcome!