Hi, Needtogain,
Let me share. At age 12, Seventh Grade I hit 6'2" which is my final height.I weighed about 115# and was so conscious of my beanpoleness that it almost ruined my life...I thought I would look like that forever. I started weightlifting at 16 and slowly started gaining muscle...maybe 140 starting high school to 160 starting college...eating and drinking all I wanted, certainly over 3,000 calories a day.
By HS graduation I was hard 180...I couldn't by a decent suit because the 44's all came with HUGE pants (36 or 38) that no matter how much they altered looked like Hell.
Then work/grad school, too much drinking I got to around 200...hmmm, whatever happened to the wasp waist the 32 inch pants? ALL of a sudden 34's??????
Well, life went on...I worked out fairly and ate a little too much and found myself, in my 50's at 239# and OVERWEIGHT...sagging boobs, TIGHT size 36 inch pants and all...all from eating probably LESS than when I weighted 170.
When I finally bought my first pair of 38's...I said enough is enough and I've been dieting for several years to take it down (I never wore the pants.) I work out pretty hard, and VERY hard for a man of my age and I'm getting much of my muscularity back so I look better (except the face


)than I did 10 years ago.
Moral: Don't push the weight gain, life has a way of doing that FOR (TO???) us.
Keep working out and concentrate on building muscle...eat only enough to provide a little more protein than you need for replacement and the weight will come. Eat good food; good lean meat, good fish, good veggies, go easy on the fats like butterfat.
Gaining even ONE pound of fat is not necessary. If you feel you need a little something extra, add a protein shake in the morning.
You are SOOO much luckier than a 23 year old at 300#...they exist.