In the following clip, a patient (Mr. Wilson) returns to a doctor's practice for advice on a recurring problem (heartburn).
"What can I do for you?" is similar in meaning to "How can I help you?" and is an effective way of asking a person to explain their problem.
Mr Wilson uses the words "same old thing" to mean that his current problem (heartburn) has been giving him trouble for a long period of time.
"Progress" means improvement, eg: "I just don't seem to be making any progress at all".
Mr Wilson's heartburn seems to be getting worse rather than better, "I'm worse in fact." The doctor, at this point realizes that action needs to be taken and tells Mr Wilson "Let me ask you a few questions, just to see if we've missed something, or to see if you've left anything out." This leads us onto the next clip.