OK. I got serious about weight training in my freshman year of high school because I joined the football team, and got involved in the lacrosse team later on.

I gained 40 lbs of muscle roughly since freshmen year, but now I'm a rising college sophomore and I have the same physical abilities since my high school sophomore year. I benched 250 lbs sophomore year, and I bench roughly the same, if not less. I don't squat very much, but I remained using 50 lbs dumbells for lunges, since sophomore year. My mile run has always been shy of 7 minutes.

For 4 whole years, I never improved, but I kept gaining weight in muscle mass. It don't know what to do!

Do you switch up your routines? Try doing some dumbbell bench press for a month and different leg work if you can. Do you have access to a leg sled press? You are still growing so your body has to expend a lot of energy on that. Don't be discouraged, just keep at it.