Learn Swedish: Har du någonsin upplevt ett sådant problem på arbetsplatsen? - Have you ever experienced such a problem at the workplace?

The key here is the word någonsin (ever). Because the question is asking about a general life experience that could have happened at any undefined time up to the present moment, we use the present perfect (har + supinum). If we asked about a specific time in the past (like yesterday), we would use the simple past (upplevde).

Why is någonsin placed between du and upplevt?

Någonsin (ever) is a sentence adverb. In a main clause question, the conjugated verb comes first (Har), followed by the subject (du). Sentence adverbs step in right after the subject, pushing the second verb (upplevt) further back in the sentence.

Why is it ett sådant problem instead of just en sådan problem?

The word sådan (such) behaves like an adjective and has to agree with the noun it describes. Because problem is an ett-word, it takes the neuter t-ending, becoming sådant. The article must match too, giving us ett sådant problem.

Why do we use på for "at the workplace" instead of i?