Yes ulcers can cause your side to hurt.
If the pain is on the left side or right side and you have ulcers that could be a symptom of your ulcers flaring up.
The pain during ulcers is usually located in the pit of the stomach or just below the ribs on either the right side or the left side and the pain is a gnawing or burning pain and sometimes the pain gets worse on an empty stomach.
If the ulcer is left untreated and becomes large enough it can eventually erode into a blood vessel and cause bleeding.