Yearly (or During Times Of Extreme Stress) Flue Like Symptoms

Yearly (or during times of extreme stress) flue like symptoms (fever, chest and sinus congestions, mucous, fever 'perception' but not registering on thermometer, pain in joints and specifically spine. lower back, hips combined with HORRIBLE soar throat but not strep)... pretty much once a year since childhood. Do I just need flue shot or could be indicative of something more? Every provider just waves me off and says I've got the flue. Probably, but it is strangely consistant and some of the symptoms don't really correlate and symptoms always the same--30 years of the same strain of flue 1 or 2x's/year? Doesn't make logical sense. Other than this and now chronic lower back pain (Started after a "flue" in 2012) I'm exceedingly healthy. Eat 0 sugar other than low glycemic fruit. Live on non-gmo, organic, anti-inflammatory veggies, low-glycemic fruits and whole grains, wild caught fish and organic eggs and some game meat...