Welcome to the community.
Yes, do check with your housing association but in most instances internal decorating is not a cost that the landlord will cover.
In which case you probably will be looking for charitable grants to pay a commercial decorator or local systems that provide 'volunteers' that provide decorating at low cost, often the 'volunteers' are offenders sentenced to do community work or young people on schemes to help them acquire skills and get work ready.
To try to identify charitable grant givers you can use the Scope grant search tool at:
Your housing association might perhaps know of local volunteer schemes but if not your could ask Care and Repair for advice:
In England: http://careandrepair-england.org.uk/
In Wales: http://www.careandrepair.org.uk/en/
It might also be worth contacting your local volunteering centre, if you have one.
Jean Merrilees BSc MRCOT
You can read more of my posts at: https://community.scope.org.uk/categories/ask-an-occupational-therapist