How is melagra described in contemporary English? [closed]

I would favor a compound that identifies the kind of thing being affected:

• muscle pain or joint pain or back pain

• aching muscles or aching joints or aching back

Expressions for pain tend to be fairly literal in English. A specific example is to feel it in (one's) bones, with it literally referring to a storm or another weather pattern. (See "Can You Really Feel a Storm Coming in Your Bones?") The feeling is a general ache that arthritis sufferers feel when the barometric pressure changes. In this case, the expression has spawned an idiom that more generally means intuition. Cambridge Dictionary:

feel it in your bones

to believe something strongly although you cannot explain why:

More generally, to capture the experience of great pain, especially over an entire body or area, racked with pain (or racked taking the part affected as the object) is a common expression. From the Oxford Learner's Dictionary:

(also less frequent wrack) [often passive] rack somebody/something to make somebody suffer great physical or mental pain

to be racked with/by guilt

Her face was racked with pain.

Violent sobs racked her whole body.

(British English) a racking cough

If someone is bedridden from pain or if their pain is particularly visible (periodic shuddering, groans, facial expressions), they may be racked with pain.

The feeling of pins and needles when your leg or arm has fallen asleep, and circulation is returning, might capture what you're looking for.

However, a whole-body pain of the sort you're describing is best captured by formication: "the sensation of having insects crawling on or under the skin."