How do you train weak muscles?

My chest and shoulders muscles are very weak. I can barely do 3 sets of shoulder and chest press using 15 pounds dumbbells. How can I strengthen my muscles in this area? should I do more upper body training?

I also have another question. What is wrong with lifting weight more than 3 times a week? what if my body is not sore and can lift 4 or 5 times.

thanks. but i don't only work on the ones i can see in the mirror, i wouldn't give a damn if i didn't have one respectable looking muscle, i would just want the strength, I don't have dumbbells, I want too be able to increase my strength without machines, which is what you  were saying, but I want to be able to increase it enough so i don't look like a wimp in the high school workout room.

I'd say "ignore them" but I was in high school too once - and kids can be mean.

So assuming you want to workout at home, and can't get a setup there, I'd recommend looking up some programs that you can do without equipment:

Body Is a Barbell

Training Advice for Generation Ent

Original Post by amethystgirl:

Body Is a Barbell

Training Advice for Generation Ent

This.  Plus lots (and lots) of food and milk.  And then more food and milk. 

(((Safina1)))

Start with one push up. Try two. I could barely lift soup cans over my head a few years ago and now I can do 34 solid big girl pushups (on my toes) and counting. Knowing that I can keep trying higher motivates me to see progress that is very simple to track.

Keep going!

>>>>>>;<<<<< <