What compound is this please? A painkiller?
It is diclofenac, which is described there as "applied to reduce inflammation and as an analgesic reducing pain in certain conditions".
By drawing the structure in emolecules (search mask here), I selected the entry as the free acid (and not the sodium salt, for example). A click on "LSKB" below the structure representation linked to the next database in which the restraint "where to find" was lessened to "chemicals in literature". Eventually I was guided towards this page, which a first entry name not following systematic nomenclature; an often seen pattern for pharmaceutical products:
To round the picture, if looking for physical chemical data, I would repeat the query, then including its salts (like the sodium salt).