Hi.

I'm having a few problems with a few of my exercises, and I'm not sure but I think my weights might be too light to build up.

I have no access to a gym so I'm having to do everything from home.

I've just been doing my shoulders today, I managed to do 100 flyers, in which I felt the burn. However when I was doing the over-head barbell presses, I got to 150 (reps of 10) and if what happened last week happens again, tommorow I won't feel any kind of pain in them.

It's a good thing to feel he lactic acid the next day, right?

And won't doing more per set just build up lean stregth? As opposed to size? Should I do more sets? The only reason why I was against doing more repetions or sets was because each workout should take about 45 mins, so I've heard, so if I'm going over that I'm doing something wrong, I'm thinking.

Thanks.
Dan.

Hi,
 
Having your workouts last no more than 45 minutes is a good thing. However, by the sounds of it your weights may be much too light if you are able to complete 100-150 reps of a particular exercise.
 
If gaining mass is your aim, you should be using a weight that you cannot complete more than 6 reps with in a single set, and combine this with a good diet.
 
This is much more likely to be the answer to your question than to increase the amount of sets you perform.
 
Also, try not to guage the previous day's workout by the pain you feel. It doesnt mean its not working because its not hurting.