anyone supplementing D3? Kel?

i am not sure if i am actually deficient in vitamin D (have not been tested), but i have been reading a lot about vitamin D and muscle tightness/knots. here is a little background on me. when i was 11 and 13, i broke my right humerous bone while playing baseball due to a bone cyst (made my bone pretty much hollow). my joints crack and creek all the time and my tendons/muscles stay tight as hell. feels like most are like a taut, like a rubber band about to pop! my legs are full of muscle knots, feels like my quad and my vastus lateralis are stuck together. keep looking, searching for answers, and wondering if that is what i have going on. want to see if supplementing vitamin D3 for a few months will help. from everything that i have been reading (examine.com), seems the range limit to daily intake is around 5,000IU- 10,000IU.

my questions, how much should i start taking to start out with? i have some vitamin D3 (1,000IU) with Calcium pills, and started taking 2, twice a day, today. that will equate to about 4,000IUs a day. how long does it take the body to build up vitamin D in your body to affect where one can actually feel the difference? should i do a loading phase?

any feedback is much appreciated, thanks!