my microsoft account(windows phone, nokia lumia 820) says its out of date and needs sync but it wont sync. it keeps giving me the error code 80070020. why is this effecting my downloading of apps?!

I have a windows phone that i have had for a while (a year) and just now it says when i just installed the new window phone update i uninstalled an app and i tried to go the  windows store and get it back, but it keeps giving me the error code 80070020, i looked up ways to fix it but all of they didnt work, so can someone plz just give me a straight foward answer or something on what the heck is going on with me poor little phone...