This may not apply if your hearing loss was sudden, but many people get hearing aids only after years of decline. Your brain adapts to what it has available and you learn to hear as best you can with the limited stimulus. When you finally get hearing aids, it feels like your ears have been unblocked.
When it comes to interpreting speech though, especially in noisy circumstances, you have to give it time. Your brain isn't used to using the extra stimulus to interpret speech. In fact, it may have gotten used to hearing loss filtering out background noise and you may initially find all the stimulus makes it harder to interpret speech because of all the background noise you now hear that you previously didn't.
If you don't have patience and start immediately futzing with volume all the time, you never give your brain a chance to adapt, and will be very dissatisfied.