Why is pull up so hard to build?

Just came back from gym. First I did bench press, and I gained 20 pounds (from 130lb to 150lb) from not doing it at all in the last two weeks. Thanks to all the ring stuff I was fooling with in those 10 days or so. I noticed that there was blood marks beneath the skin on both of my elbows, what might have caused it?

Then I took a few minutes of rest and tried pull up, I grabbed the neutral hand position bars and I managed to crank out 7 in the first set. (I did eye level to the bar on the way up and almost straight arms on the way down), I have never done so many in a row in my life! Later I did 15 more in the next 3 sets. For a moment I felt I had over-accomplished something and actually got scared for a bit. LOL!

Thanks for all of your advice! I will definitely continue doing it until I can do 30 in a row then I will switch to something else.

Can you image what kind of stuff I will be doing when I stop shaking like a vibrator on the rings? oh baby, I can't wait to see!

p.s. I am giving myself a reward by enjoying a can of Campbell soup right now.

I think you need to stop being so silly and over sensationalizing some of your training as to shaking on the rings.

Good job on the progress though.

Can of campbell soup?

You should try something better like steak, a cooked chicken, pork chop, etc.

Improved my bench to 160 (finally surpassed my bodyweight)

But I died on the 5th pull-up on the 1st set, lol! It's still pretty hard.

What kind of routine are you doing right now?

I found that the last few inches on the top had always been the hardest for me. How do you build the strength to pull the bar to your chest level?