It is really hard to tell even from the details in your story without a photo. But.....if you are growing in a container overwatering is one problem. Punch some holes, either in the bottom if you can or around the sides near the bottom. Let the soil get almost dry before another watering. Then remember to add liquid fertilizer at 1/3 strength every couple of weeks since watering will flush out any nutrients available in the current soil.
You may have had something on your fingers when you pinched off the leaves that caused the curling. More likely just pinching off the top of the plant will cause stress on the plant. Much of the health of the plant comes from the extremities. While the rest of the plant will provide energy the ends do a great job of keeping your tomato plant healthy. In my opinion you do damage to the entire system by pinching off parts. Just let it grow naturally.
If the plant is maintaining its color and vigor other than the pinched area, you will most likely be OK. Just get some drainage or you will see the leaves yellow and wilt from drowning the roots. Good luck.
