Simplified example: the value of most stock companies depends on their projected gains in the next few years. A projected gain of $X in 5 years will devaluate over time as inflation increases, simply because $X in 5 years time will be worth considerably less than $X today. As inflation rises above a healthy 2-3%, it hurts the actual gains and thus the connected stock. You can counter such things by keeping interests low (as they've been doing for a while now) but that party has to end someday.

Only certain wages. Like public servant wages. Private companies paying normal people regular wages aren't forced to give them a raise. The minimal wage may inflate but if you're paid above minimal wage, there's no guarantee you'll see a raise.