Schmorl's nodes are very common. They are usually not caused by real trauma, but are rather considered by most to be a "degenerative process", meaning that they occur due to "wear and tear". Virtually everyone over the age of 60 has a Schmorls node present at least one level within their spine. Schmorl's nodes with associated edema or inflammation are also quite common. Some radiologists, including myself, believe that every Schmorl's node has an "acute" phase with inflammation before healing over time. Many of these are asymptomatic (IE we see them on patients getting an MRI for something completely different) and it is very possible that the Schmorl's node on your MRI was/is not the cause of your symptoms.

Traumatic Schmorl's nodes are a completely different entity with a similar imaging appearance, but are most usually also associated with an endplate or compression deformity, which your MRI does not demonstrate.