Uyk7, there is a NON service connected pension if you served in a time of conflict, it is not necesssary to have served in combat. If the thyroid is keeping you from working after medications are tried, then you could look into the pension. 100% is presently $824.00 per month, and qualifying is difficult - there must be minimual assets, no more than 60 days of incarasion per lifetime, discharge other than dishonorable, and a few lesser things also. People other than military also qualify, such as merchant marines whom served in the right place at the right time, and other exceptions, includeing civilians whom were work assigned to combat areas.
To gain a service connected pension you must produce a positive link, via medical definations to show that you recieved the disability via military action while on active duty. Discuss this with your local vets rep, the VA does vary via different locations. Medical services should be available to you if you qualify the time era, income restrictions, ect.