I am 57 years old, male, and active, and have been on Warfarin si...

I am 57 years old, male, and active, and have been on Warfarin since 1987 post Aortic Valve Replacement. I was quite happy with the dosage up till 2001, when I had an episode of TIA due to a malfunctioning thyroid and when my heart rate went down to 30 bpm. Since then, I have also been on a daily dosage of thyroxine, just enough to get my TSH up to normal levels. Since then, I have a creeping condition of body aches and back pain, which has now, after 7 years, become chronic. This does not seem to alleviate with change from the Eltroxin from Glaxo, to Thyronorm from Ranbaxy. I have now accepted to live with this sometimes-chronic pain. I tried some experiments with my dosages of the medications, and so I reduced my Warfarin to 5mg from 8mg. Within a week I was plagued with cramps and aches, and I got scared and went back to my old dosage. Has my body, my heart, my arteries, adjusted to the thin blood over this time since 1987? Due to this thinning of the blood, will the detection of constriction of arteries and veins be more difficult? And consequently the detection of angina pectoris and atherosclerosis? Or can it be just old age catching up? If any of you are on a similar combination of these two drugs and with similar symptoms, I would appreciate a line.