Hypothyroid and edema go hand in hand. It slows down metabolism and the lymphatic system. I have been going through the same symptoms you have. I was diagnosed with Hyperthyroid for the past 20 years until just recently they discovered I do both. I think they call it viral thyroiditis. Example: in December I was hyperthyroid and in February hypothyroid. The doctor doesn't want to medicate me because of the hyper/hypo swings.
I am going for more blood tests and will be seeing him in a few weeks and this time I want to go through the xrays and stuff because I am experiencing thyroid pain at moments, I have a goiter (swollen thyroid).
I hate when the doctors say exercise should help... really? I too have started experiencing difficulty walking sometimes.
I will keep you posted and would very much like you to keep me posted too.
Talk to you soon.
Diane