Pec Workout

I have recently started running and notice my thigh have got bigger(tighter jeans)? i am trying to reduce the size of them, so am dieting and exercising. Although my bum has gone down in size a little

I lost a ton of weight with cardio. I’m a lot healthier and I look a hell of a lot better but I need some muscles. Skinny boys tend to get their arses kicked.