I have a teenaged son so I can say from experience that you being 14, will ignore all advice that does not already fit in with your plans but I am going to try.

MY goal is just to look lean and maybe gain some muscle, my weight is now 67-68 kg. I have cut out most drinks other than water, but treat myself to some lemonade once or twice a week. I try to go to the gym atleast 5 times a week, but I pulled a muscle in my shoulder yesterday, so might have to give it a break. I have alsoe cut out late night snacks/ second helpings.

Your goal to look lean is a good one but not the one about gaining muscle because you are going about it all wrong. At your age and height, 67 kilos is normal weight. See for yourself - https://tdeecalculator.net/result.php?s=imperial&g=male&age=14&lbs=147&in=69&act=1.2&f=1

The reason you have a big gut and man boobs is less to do with your health and more to do with possible sedentary lifestyle, as surmised by going through your profile.

Weightlifting will help you but you will be far better served by HIIT style cardio, cycling and swimming. Otherwise, you will just stunt your growth and whether you have short-term benefits or not, will regret it for a lifetime.

week, but I pulled a muscle in my shoulder yesterday, so might have to give it a break. I have alsoe cut out late night snacks/ second helpings.

If you pulled a shoulder muscle, you are doing the fitness program wrong. For your age, you are far better off doing the Starting Strength program. For guidance, you can watch the Alan Thrall videos - https://www.youtube.com/user/athrall7/videos

Be thankful for those who are teasing or bullying you. Because of them, you are focusing on getting healthy at a far earlier age than most. At the same time, if you let them affect you, they have won and you have lost. Are you really going to let that happen?