meaning - How to say the opposite of "It can be a pain"

This maybe a bit of Chinglish thinking.

For example you can say

It can be a [noun]

meaning

It's possible that this is a [noun]

Using pain as an example:

If you want to say the opposite, not sure should you say

It can not (to?) be a pain

since that feels like "It's not a pain" but not what I want to express:

It's possible that it is not a pain

I think this might be a better example:

I want to express the opposite of

You can choose this one

Which is:

You can choose not to choose this one

But I am after a shorter version of it.

I feel one way would be to say

You cannnnnnn, short pause, not to choose this one