vit D deficiency is not routinely checked in the UK, is has to specially ordered and only if it is very low will they check your calcium levels.

Vit D can be got by two methods, first sunlight, it is possible that your body is unable to exchange this into usable vit D, last summer i spent hours in the sun most days without sunscreen, but still tested low vit D...i did have a great tan though! the other way is orally, not many foods contain usable vit D in any great quantity, but you can get suppliments containing it, you could possibly be unable to absorb it though.

you can be outside all day in the sun, but if you use sun screen, sit in the shade, cover your arms/legs with long sleeves/trousers or wear hats especially wide brimmed ones you are not going to absorb enough vit D as you need direct sunlight to allow your body to absorb it, driving everywhere does not count either unless you have a convertible with the roof down!

low vit D is definitely a big culprit for aching bones, I told my doc that my bones hurt on the inside years ago, he did nothing, it got worse, i was unable to walk without support, got depressed tried to end my life because of it with rat poison only to find i felt a million times better the following day, the reason why.... because rat poison uses very high levels of vit d as the poison and as my body was so low the level was enough to bring my levels back to near normal not overdose levels! I do not advocate that you try rat poison, it is not a good way to get you vit D, but you could try suppliments of calcium with vit D as one needs the other to help it be absorbed into the body.