You need to ask whether something exists, is present, or is available. Use Is there + the noun: Is there a pharmacy near here?
Is there any coffee left? You're checking whether some is there at all, not which coffee.
Once you know it exists, state it instead: There's a problem with my order. Compare Is there a problem? Same noun, opposite knowledge.
You're asking about something in a place
You want to check a place before you act: Is there any milk in the fridge? You're not asking which milk, only whether some is there at all.
You're at a counter or on a call and need something available: Is there a quieter room? It works because you're asking if one exists, not pointing to a specific room.
Someone's stopped you in the street or knocks at your door: Is there a problem? You genuinely don't know whether anything's wrong yet.
If you're naming the thing yourself instead, with a singular noun like this, the statement is There's a problem with my order. You already know it exists. See the next section for when that switch matters.
When you're naming the thing yourself
The condition changes the wording: once you're naming the thing yourself, you already know it exists, so you stop asking and start telling. There's a problem with my order. Compare Is there a problem?, which only checks whether one exists at all.
So before you speak, ask yourself one thing. Do you want an answer from the other person? Use Is there: Is there a doctor on board? If you already know, state it: There's a doctor on board.
At a service desk, this difference matters. A customer who knows the issue says There's a charge I don't recognize, while one who suspects something asks Is there a charge I don't recognize? Same nouns, opposite knowledge.