"Given no time to discuss multiple ailments"

I took my elderly mother, who is in her 80s, to a GP appointment as she has been suffering with a severe cough (she has asthma for which she was recently hospitalised), excruciating rib pain and severe shoulder pain that was not being controlled with paracetamol (arthritis). We sat down in the consulting room and the GP asked what was wrong. We explained about the cough and the rib pain and she examined her. She explained what she thought was wrong and prescribed some meds/tests and explained that this might be a related thing. I then prompted my mum to explain about her bad shoulder pain and the GP abruptly stopped us before we could go any further and said she was not prepared to discuss a "third" ailment at today's consultation! She said she was not prepared to keep others waiting and she had a child to pick up. I totally understand the pressure of GPs and their appointment times, but to say that to an elderly woman "you have to make another appointment to come back " I thought was inappropriate. She went away with no pain killers, so she is still in severe pain and because she cannot attend the surgery by herself, I have to arrange time off work to make another appointment to discuss her third complaint. I was quite speechless. I pointed out it was just a prescription, but she was having none of it and we have to go back to discuss the third ailment. If it had been a young person with several unrelated ailments, I would have understood, but to send an elderly lady away in pain and told to come back, I do not think was very professional, despite the GP's pressure to keep appointments. If this is the current practice for appointments, then the GP surgery should put a large, clear, informative sign up in the waiting area explaining the procedure for appointments, so you can decide which ailment you feel is more urgent, if you have more than two.