If I have to talk more loudly than normal, or sing, I get hoarse very quickly. Equally, I can’t shout as I did years ago, when I could have done a sergeant-major proud. This is all basically due to lack of use - I’m normally a quiet person and don’t speak much anyway - but I’d like to get the facility back, so what vocal exercises do I need to do?
Cough. 
My advice is to find an actual voice teacher to work with you one-on-one. Diagnosing and working with a voice without actually hearing it is very difficult.
In general terms, I would suggest that your problem is probably impulsing the voice from the throat rather than from the abdomen, leading to tightness which will quickly lead to hoarseness. Allowing the breath to do the work will also help the glottis to remain open, which will increase resonance and allow for a fuller sound without pushing.
That’s about as far as I can go without actually hearing you and working the voice directly. Hie thee to a teacher.