From the tone of your question, Lubeelu, I get the sense that it has been in this pot for the whole of the seven years. Therefore it will be potbound, have used up all of the nutrients and there is so much root material in the pot that water cannot get down there. So yes, It needs re-potting into a larger pot in a good ericaceous compost.

It would be a lot better planted in the ground noiw. If you can't possibly put it in the ground yes do repot it in a bigger pot.- with new compost it won't need feeding for a while.
The new shoots could have been damaged by frost and/or high winds.

Thanks for your answers - I haven't really got the room to plant it in the garden, there's space on the shady side but not in the sun...and up until now it's been quite happy! Although it's in quite a large pot already, I thought it probably was time to repot. Poor thing!

Pieris is generally happy in shade, so I would plant it in the ground now if I were you. Yes, you can repot, but you'll have the same problem again and again, until you get to the stage where there is no pot big enough (I speak from experience...!).

I see you live in Hertfordshire like me and my soil here is alkaline and not suitable for Pieris which prefer ericaceous (acid) soil - see Bulbaholic's post, so best to check your soil type before planting in your garden.

My Pieris which is in the ground has been damaged by the late frosts and hailstones which we had last week so it could also be the same for yours.

Like Jaykaty, I live in Herts. and have neutral/alkaline soil, so my Pieris is planted in a raised bed in ericaceous compost. It is only just beginning to show the red bracts, so maybe yours will come soon. With a larger pot and fresh compost, let's hope it will thrive.