I read that Sai Baba said something about hunger and back pain that was very specific to Laxmichand. What's the story behind that?

This is a profound example of Sai Baba's inner knowledge. At the time when devotees brought bowls of khaja to the masjid, Laxmichand was feeling particularly unwell. He was suffering from hunger pangs and also had a pain in his back, which made him feel restless. Just at that moment, before the arati, words came from Baba's mouth that directly mirrored Laxmichand's private suffering. Baba said, "Hunger has come, that's good. There should be medicine for back pain." Chapter 28 explains that this was like an "echo without sound," where Baba articulated the exact thoughts and physical state of Laxmichand without being told. This event made Laxmichand realize that the Maharaj possessed deep inner knowledge of everyone's condition, which greatly strengthened his faith.