Help with paragraph

Hello, ..

Can you please help me with following paragraph.. I came across this as I was reading online about neck problems:

"Aim to keep your neck moving as normally as possible. At first the pain may be bad and you may
need to rest the neck for a day or so. However, gently exercise the neck as soon as you are able. You
should not let it 'stiffen up'."

- When it says at first the pain may be bad and you may need to rest the neck for a day or so, does it mean rest is needed because the pain may be bad (in which case rest is not necessary if there isn't pain), or the two points are independent but coexist? is and there for reasoning/explaining?

Thanks.