There are some general rules for treating pain and trauma. . . and they have little to nothing to do with any Zangfu diagnosis method you learned. Acupuncture is channel based rather than Zangfu based.
To treat pain and trauma/injury:
Identify the channel or channels that are involved. Use palpation and the location of pain and tightness to identify the channel that is directly involved.
Use palpation of coupled channels to determine which channel to actually treat. You could treat directly on the affected meridian, or you might decide to use a related meridian instead depending on reactivity to palpation. As an example, I once treated a guy who had just separated from his wife. The dissolution of their marriage was not a happy one and there was a lot of anger on both sides. The man had moved in with a friend and was sleeping on the friend's couch. His chief complaint that day was that he had woken with a stiffness and pain in his right hip and radiating pain down the lateral aspect of his leg. He had also had a frontal headache for several days prior and even had a tight, bunchy looking muscle visible right around Gb 14 on the right side. He also had a cramp in the top of his right foot that wouldn't go away right around Gb 43. Are you seeing a pattern here? Anger --> pain and tightness on the Gallbladder channel. The old Master Tung saying, "When the baby is hurt, don't hurt the baby" means you don't directly treat the affected area, so I didn't want to needle the Gallbladder channel. When I palpated the Pericardium (upper Jueyin channel), I found tender points. I needled an ashi point between PC 3 and PC 6, PC 6, PC 4, and PC 7. By the time I got to PC 7 most of his pain was completely gone. I left the needles in about 40 minutes and did some cupping around the GB 30 area. He walked out instead of limping. Four needles, five cups. That's all it took. What did I do? There is a husband/wife relationship between the Shaoyang and Jueyin channels. Granted, we learn them as Gallbladder/Liver and San Jiao/Pericardium, but the mirroring of the channel pairs still works, coupling Gallbladder to Pericardium. The other thing I did was to use the Pericardium channel as a kind of microsystem for the body. PC 7 represented the pain in the head. PC 4 is the Xi Cleft point on the channel, so I used that for pain. PC 3 was used to treat the pain in the guy's foot. I used the ashi point between PC 6 and PC 3 as a mirror for his hip pain and sciatic involvement. I used PC 6 mostly to relax the guy and because I know that the Jueyin here would talk to the Liver Jueyin as well. If this guy hadn't jetted into my office 5 minutes before close and begged me to help him out, I probably would have gone on to do Robert Chu's WTH points at the very least to help settle this guy's Liver.
Treat with as few needles as you can to still get the job done. Balance the affected channels with imagery, channel relationships, point properties, and point functions. Make smart use of the 5 Shu points (jing well, ying spring, shu stream, jing river, and xi cleft). Use guiding points to direct the energy where you want it to go. Any time you can combine imaging, mirroring, and point function, and get good results, you are totally winning as a practitioner! Dr. Robert Chu has a number of three point combinations using Ling Gu and Da Bai with guide points. I liken this to firing up the engine of a car (Ling Gu and Da Bai), then deciding where to drive it (the guide point/s). As an example of this, If you need to treat pain along any given meridian, needle Ling Gu and Da Bai on the opposite side to the pain, then add the Xi Cleft of the affected channel on the affected side.
If pain is one-sided, needle the opposite side of the body. Use a guiding point or points on the affected side. Now. That said, don't get too tied to this "what side to use" business. You are treating a whole person, not a left side or a wrist or an ankle! Acupuncture and Qi are smarter than that.