yeah, just bought it, seemed spot on, but now its shaking and whirring, seems to come from back right wheel, but cannot be sure

just bought a freelander, my first in the landy realm, was all fine till i set off home from supermarket, not the bitch is shaking like a pig on heat! I came up a 16% bend and hit the gas to pull me up, now its shaking and making like a whirring noise, any ideas anyone?