Pepper leaves curling and distorted
This might be a sign of a mosaic virus.
Greenhouse plants in early spring may be subject to leaf-hopper or aphid attacks. Leaf-hoppers, especially, carry diseases. At the same time, they can cause plant damage - without being disease vectors. It's hard to tell, but it seems that there is a whitish "thing" on one of the leaves in the left-hand photo - insect?
Sometimes environmental stresses can cause leaf-curl (like being near the door), but it is more likely that you have a disease problem.
If it is a mosaic virus, it won't necessarily kill the plant but it will reduce yields, and will spread throughout the greenhouse, and other plants. If so, you should get rid of these plants and the soil they are growing in, and monitor your other plants for similar symptoms - there is no cure for a viral disease.
Finally, you may want to bring a sample into our diagnostic clinic:
I hope this is helpful. Please contact AaE again if you have further questions.