Many doctor told me that i have a pulled groin but why do i feel the pain below my 3to4 inches of my belly bottom.or could groin be in pubic or pelvic?

Could be a strain,or: 3-4 inches below the below button would be middle of lower abdomen/upper pelvic area. Possibilities include a muscle strain, which can be painful for couple weeks. But could also be something related to the urinary bladder, or lower colon. Since your 17 years old, and did not mention any urinary tract symptoms, my bet would be on a muscle strain. Many docs? Maybe check further for GI or gu problem.