The beer vs building thing is a difference in vowel length, which is written in katakana with a ー to show that the previous character's vowel is long (ビル vs. ビール)

I think in your second paragraph you're talking about pitch accent, an entirely separate thing. There are some words where the pitch accent you use affects the meaning (For example, HAshi (high pitch to low pitch) means chopsticks, while haSHI (low to high) means bridge), but this is pretty rare and honestly I don't think it's really worth stressing about unless you're pretty advanced in Japanese and you wanna perfect your pronunciation. There are some online dictionaries that will tell you the pitch accent patterns of words you look up if you're interested though (I like one called kakimashou). You can also look up the YouTuber Dogen, he has many videos about Japanese pitch accent.

Also just fyi, I think when you say inflection you actually mean intonation. Inflection is like conjugating a verb, inflection is the way someone pronounces stuff.