Matchmaking in this game confuses me tbh...

Ive noticed the past two weeks I've been playing that the games have been rougher to some degree. Yesterday i went onto lolwiz just for the recommended build and i noticed i was going against mostly golds and a diamond 4 player. Im silver 4 in solo duo right now and bronze 1 in flex, so i dont get why im matched up with "higher tier" players. To be honest im ok with it too some degree because it seems too be helping me become slightly a better player. But it can get somewhat hard in ranked games and can be frustrating.

So overall i was just wondering why is this. If anyone has any tips or suggestions or just comments about this let me know i much appreciate it! Also Im not the best at this game so please no negativity.