Loud feedback/noise on TDA7931PD.

I've been making a mono channel audio project which uses the 7391PD amplifier. I designed the circuit according to the ST datasheet schematic (below) but when I turn it on there is incredibly loud feedback (especially at the input audio jack). I can even hear it picking up radio when I attach an audio source (a phone without any music playing). So I'm thinking that perhaps I haven't grounded it correctly; I've checked and everything seems in order. I also haven't included a volume control so could it just be the gain is really high? Should still be fairly noiseless at max volume no?