Hi Louise!
People only tend to tell you 'the horror stories' - it's human nature. They don't tell you about the vast majority that are extracted uneventfully. If the wisdom tooth is fully through into your mouth, then they are not really any different from extracting another tooth. It's only when they are still not fulyl through that they CAN be more difficult.
You need to discuss the procedure with your dentist. They can advise you as to how easy the process will be, and the approximate time involved. Also if the extraction is likely to be a 'surgical' where the gum is temporarily lifted back from the tooth to allow better visibility and access to the tooth. You can then make an infomed decision about having just a local anaesthetic, sedation of some kind, or a general anaesthetic if need be. Your dentist will advise you on the three options, and the pros/cons of each.
For any extraction, you would expect some post-operative pain for a few days, possibly some bruising also. This is normal. Sutures (stitches) are often used to help position the gum afterwards, and this is quite normal. They can be self-dissolving ones so as not to need having them removed afterwards. Your dentist will also discuss any other possible risks involved.
Please discuss this with your dentist and you can then both reach the right decision.
Hope all goes well.