Vitamin D Deficiency - Neck And Shoulder Pain - Tired And Dizzy

I've been unwell for on and off now for almost a year. I remember phoning off sick a couple of times before feeling tired and 'achy'. I thought I was just being lazy and this was psychosomatic. Then I started getting really ill when I developed a sudden onset of neck/shoulder pain which is still an ongoing problem now although the pain has turned into discomfort/ache which I have learned to manage doing exercise and stretches. I also feel sensitivity on other parts of my body (like invisible bruises.For 6 months I was coping with my neck/shoulder problem (symptoms are crawling/tingling sensation in the arm, sensitivity to touch like its bruised and cold feeling and dull ache on my shoulder blade).

Then gradually I started developing 'flu like symptoms' without cough or cold but with tiredness/fatigue and dizzy headache which are intermittent throughout the day, until 2 weeks later I started getting throbbing ache in my legs and eventually I couldn't sit all day without getting restless legs and crawling/tingling sensation in my legs which caused weakness in my legs and worse when I'm going upstairs - and my knees keeps clicking. I went to my doctors who prescribed me with naproxen. And told me that I had something called Reactive Arthritis, which i thought was a misdiagnosis. Overall I thought that it could be viral related

This time I've been off work for a week when I started to feel better after a week on naproxen. I came back to work for a week feeling like i thought I recovered. Then boom 2 weeks later gradually the flu like symptom came back with extreme tiredness / fatigue and I've been in bed since. I'm still achy all the time regardless. I have no energy to do anything, even showering is a struggle. I've been in bed most of the time, sometimes I try to go out with my husband for a few hours but I come back home absolutely exhausted and the soreness/headache i get is a different level. Most of the time I feel like my body is inflamed.

So i decided to get a second opinion and i went to see another GP who referred me for a blood test. A few days later, my results came through and I have Vitamin D deficiency. Everything else they tested seem fine. I have a better outlook now though after the diagnosis, apparently it will take months for the treatment to take effect. I guess now they found something they will stop investigating further (which worries me a little bit) but i guess its process of elimination so treat one thing at a time. Would be great to hear from others who also has this deficiency and whether the treatment was effective?