Well don't get discouraged at all because everyone has those things when learning guitar that are easier for them and other things that are more difficult for them. It really differs from person to person.
Seems that you really find strumming songs like 'About a Girl' easy to play, and have a bit more hard time to play some leads. Since you only have been playing for a couple of months I suggest you take it slowly and a comfortable speed, and keep practicing. I'm sure you'll eventually get there.
I myself couldn't strum properly at all when I started out with guitar. I nicknamed myself 'mister irregular robot arm' and thought I could never get it down. But as long as you practice hard and slowly those things will get better. And look at me now, I can pick up the strumming pattern when I hear it!
I don't know what you're struggling with specifically but since the 'In Bloom' solo has a lot of bends maybe it would be a good idea to practice those and also picking out notes on single and few strings.
Hope that helps
JJ