Should i be worried if...
my sound somtimes goes out? like when im shooting the machine gun my sounds go out completly i can't hear anything like the gun shooting or splicers screaming. so should i be worried? or is that just part of the game
It's definitely not part of the game, but I don't think you have a reason to worry, yet.
Firstly, are you playing on the Xbox 360 or a PC?
For the Xbox 360, check to make sure your connector cables are all securely connected to your TV/speakers. Make sure no residue is on the cable connections, and no wires are broken or exposed. Check your Xbox for heat problems (a thermometer behind the exhaust port works fine, below 30C. is preferred). Check the disc for scratches, smears, or problems. Clean if necessary. Try turning off unneeded power-consuming items on the same circuit.
For the PC, you've got a bigger challenge. Go to Start > Run..., and type in "dxdiag" (without the quotation marks). Let the window load, then click on the "Save All Information" button. Save anywhere you like, then copy and paste the ENTIRE document here. This'll help determine if you've got a hardware/driver/software issue.
I have some POS sound card but when I encountered my first Big Daddy most of the sound wass completley washed out..idk if it was from me sustaining damage or not however :S Any thoughts on this as well?
Damage taken by the user shouldn't affect sound quality, but a LOT of stuff happens in a Big Daddy fight and it may have been too much for your audio hardware. If your soundcard is integrated into your motherboard, I'd recommend going off and buying an Audigy, or something similar, which can cost under $30USD if you want it to.
that same thing happens to me, though it is very rare. i only notice it when shooting the machine gun.