Growth very unlikely. An 19 yr old is not growing taller if his growth plates have fused. If not fused, he will grow a little bit (pediatrician's growth chart for him can tell if growth has stopped). To look taller, one can choose properly designed clothing & shoes, and have good posture. Vitamins, supplements, "special" foods, exercise, etc... will not make a person living in the U.S. taller (height here is genetic).
Probably not. Agree with dr. Kwok's answer. If there is an underlying medical condition such as celiac sprue, inflammatory bowel disease that led to growth retardation (bones not yet fused), can perhaps get a delayed growth spurt once the condition is treated. An xray can give bone age. Most likely you have attained your adult height.