Three days after a deep tissue massage, I ended up in the hospital with pneumonia. Was this directly related?

Massage pneumonia. Likely coincidence....Shouldn't be any connection.
No. Pneumonia is caused by germs that enter your airway and set up residence in your lungs. It can occur after a preceding URI or start abruptly with no warning. The most common bacteria are often found in the nasal passages in otherwise healthy people. Deep massage on your tissues & muscles doesn't give you new germs or send "bad vibes" to your lungs. There is no reasonable way to link the two.