Curled leaves and branches on tomato plants are often caused by stress.
Of course, disease, weather conditions, and soil problems, including under and over watering, can cause stress and leaves and leaf branches to curl.
However, this often happens in the early summer when plants are still developing their root systems and we get warm sunny days when water uptake is greater than plants can cope with at their stage of development - especially if they are growing in containers.
Sometimes if roots have been damaged by over feeding or disease, this can cause a restricted uptake of water by a plant.
Usually curled leaves and leaf branches return to normal growth when temperatures become more stable and roots have had more time to develop a system that can cope with higher summer temperatures.