workout and diet

[Totlkaos11]

hello everyone,
i'm new here and wondering if someone or multiple people could help me out. i am 19 years old i weigh 175 lbs and am 5'11" and my body fat is 15%. I want to gain about 25 or more pounds of lean muscle mass. I seem to hit a plateau in my workout. I have tried changing it up but still minimal growth. Also i would like my body fat to get down very low. I can follow a diet easily as i do now. maybe i need to change that but its mainly high protein medium carbs and medium fat. any help would be great.
Junior

 

[Totlkaos11]

to add to this i workout 6 days a week with 3 days of cardio. day 1 back, day 2 arms, day 3 chest then repeat for the other 3. i would also like to lose the fat from my love handles and my abs(thats where most of it is). 1 thing i would really like to see is some growth and thickness in my lats. thanks for the help