Twisted neck is amongst items for discussion, linked to small difficulty in travelling (6,8)
I believe the answer is:
motion sickness
'difficulty in travelling' is the definition.
The definition and answer can be both states of affairs as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'twisted neck is amongst items for discussion linked to small' is the wordplay.
'twisted' indicates an anagram.
'amongst' is an insertion indicator (I've seen this in other clues).
'items for discussion' becomes 'motions' (I can't justify this - if you can you should give a lot more credence to this answer).
'linked to' means one lot of letters go next to another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'neck'+'is'='neckis'
'neckis' anagrammed gives 'sickne'.
'sickne' inserted inside 'motions' is 'motionsicknes'.
'motionsicknes'+'s'='MOTION SICKNESS'
Can you help me to learn more?
(Another definition for motion sickness that I've seen is " It may be suffered when travelling".)