It also looks to me as if you might have several plants in one pot? Can't tell for sure from the picture, but . . well each plant needs its own large pot to grow to a good size and bear peppers.
Leaves sometimes are deformed like that by aphids, which suck on the newest juicy growth, and cause the leaves to form crooked or curled. Spray the plants off with a gentle spray of the hose, then watch carefully for pests on the stems and back sides of the leaves especially. A spray of soapy water once in a while will get rid of white flies and spider mites too.
Agree with everyone else - pepper plants need full-on sunshine all day long. As long as they're getting enough water and nutrients they will grow in just about any heat and sun.
