I am 19 years old. I have a pain in my left thumb joint, I am right handed so dont use my left hand for much. I have no swelling or stiffness, just a pain when i press on the thumb joint or when i try and do something with it or move it.
It could be a vitamin deficiency.... try taking Prenatal vitamins. They are more complete than any others. (You don't have to be pregnant to take them - I'm 70 and I take them).
You might also need to supplement your multiple as they don't contain enough magnesium. Look up magnesium deficiency and see if it fits any of your symptoms. Most of us don't get enough magnesium in the food we eat.