Patience! These things don’t happen overnight.
We all learn at different speeds, but yes everyone has the same problems for a time. Creativity is linked to experimentation, listening skills, retention of learned material, amount of time spent on the instrument, etc…it doesn’t just “happen”…it is another learned skill…varying how we play something while retaining the main theme
Yes, it will get easier…the more it’s done the easier it gets.
If you’re doing Wreck of the old '97, you might do some listening to Footprints in the Snow…very similar melody sections but usually played fairly differently…might give you some ideas…
If what you’re trying gets too frustrating or you’re getting too discouraged, have something else handy to work on for a while, then come back to it…Sometimes it takes a break from something to let the brain catch up with a new thinking pattern.
Hope this helps some…Good luck, and work on enjoying the process of learning…demanding time limited results from yourself is not a great goal early in the playing process.
Dave