I wake up often with tingling in my fingers. They feel heavy and takes some effort to bend until I can get the blood moving. Also, experience very blurred vision at times. Bladder control has become difficult at times. At times, I have extreme heal pain that goes away after walking for a period of time, but comes back after sitting or lying down. This symptom comes and goes, and I haven't been able to pinpoint what brings it on. I recently had a nuclear stress test that showed no abnormalities in blood flow to and from the heart. I have a yearly physical done and results are normal except a slightly low sodium number, which shouldn't cause concern seeing how I drink a great deal of water. I am 45 yrs old, smoke a pack a day, and drink alcohol 3 to 4 times a week, no meds besides an over the counter pain reliever every now and then. What can be causing this?