If a 14 year old boy has chest hair and facial hair that you can see a little bit the day after shaving can he grow 3 more inches?

Growth. This is not really related. Depending on several factors, genetics being the biggest determinant, growth can continue into the mid-teen years for males. A little bit of chest or facial hair won't determine if there is more growth potential. Talk with your pediatrician who can review your growth chart with you.
Yes. 14 years old boy is in growth spurt period and will grow 3inches more. They keep on growing till 18-19 ears of age.