Is it possible an underactive thyroid could make my carpal tunnel syndrome & raynauds phunomenom symptoms worse?

Good question!!: My research today yielded evidence that, indeed, thyroid deficiency is a risk factor for both. Here's a reference for the raynaud's: http://www.Ncbi.Nlm.Nih.Gov/pubmed/7387277.

It can with CTS: Hypothyroidism can lead to fluid retention which can in turn worsen cts. Very unlikely though that the same will apply with regards to raynauds. Hope this helps.