Help out...I will give you 10 points...Why can I only sometimes?

u r wayyyy to cute to b stressed. omg! i got something u can do pull-ups for. lol. jk

You say you "lift 3 times a week."

You know that lifting weights won't really help with pullups right?

The only way to get better at pullups is to do more pullups.

Do sets with your foot on a box to make them easier, until you can do regular ones.

Do pyramid sets. 1, 2, 3, 2, 1.

Just keep doing them and you will get better.

try doing pyramid pull ups do 1 pull up than 10 push ups than 2 pull ups than 10 push ups than 3 pull ups than 10 push ups all the way up till your max pull ups than start going back down 3 2 1 and keep doing push ups in between. that's what helped me out alot

Drink a protein shake, do some breathing exercises, and force yourself to do 3.

I used to be able to do 50 as a soccer player in highschool, but now I can only do 10. All it takes it hard practice. I'm sure you will be able to do it.

Maybe something isn't recovered yet before you do pullups again. Like Biceps are used a lot during pullups so maybe, for example, you worked out your biceps wednesday and tried to do pullups friday. the 2nd day is usually when your muscles are the most fatigued so maybe that's making it harder for you to pull yourself up.

do 20-30 pullups a day youll slowly progress and be able to do more at a time

They'll ship you out regardless of your physical fitness. We had guys at boot that couldn't do any pull ups.

man, im going to the army (im underweight right now). I can do 13+ pull ups in one minute. but i weight 110. You have to want it. you have to see yourself making it. confidence. if you dont have that, you will never make it. goodluck to you brother!

You're basically trying to curl 170+ pounds between your two arms. It isn't supposed to be very easy...just keep practicing till it hurts.

Just keep on trying than u will gain the muscle and you will be able to do more and more as you get stronger;)

It could be because your not strong enough yet.... Or the technique and the way you do it. Keep lifting weights and trying.