Get that Testosterone level checked if any of this sounds familiar. I'm an avid 4.5 tennis player who is fast approaching 5.0; not as in the USTA rating (don't think I'll ever get there), but rather as in decades on earth. I'm also a lifelong fitness obsessive who has always taken very good care of himself. Though I've always supported my tennis with plenty of weight and aerobic training, It's always seemed like I suffer more aches and pains - including tennis-elbow, shoulder pain, sore feet, etc. - than nearly all of the far less conditioned guys I play with. Whereas they could play three or four days in a row without problem, I struggled after just two. Playing three days straight would leave me feeling like I had the flu. Within the past year my energy has plummeted. ..To the point where I needed to take a full 30 min. nap (sometimes in my car) before taking to the court, otherwise I'd be very sluggish w/ slow reflexes. It became a problem with work where I needed to take a catnap before driving back from account visits. ..So off to the doc I went thinking I have lyme disease, mono or something more scary. The doc ordered a bunch of blood work. To my surprise, my T level was 196 which is about the average for a 75 year old. To rule out the affects of a virus or lab variability my doctor ordered three more T tests over several weeks. They all showed similar levels. ..Then a brain and scrotal MRI to rule out pituitary issues and testicular cancer. ..Both were fine. So the diagnoses was primary hypogonadism and a script for Androgel 1.62% was proposed. Fearful of the side effects, I was very reluctant. But the doc informed me that leaving it untreated meant risking osteoporosis, cognitive decline, and heart problems later in life. The goal is to raise my T to the 400-600 range. ..So I agreed and have been taking it for about 3 weeks now. I bring this up here because the affect on my tennis has been terrific. ..Not because I'm playing with greater strength, or endurance (though both have improved slightly) but rather b/c I'm no longer plagued by these constant aches and pains. My shoulder pain, TE, and foot pain have improved considerably. ..Plus, my overall recovery time is MUCH improved. I'm able to play consecutive days without feeling increasingly weary. So if any of this sounds like you, it may be worth your while to ask your doc for a T check. ..But don't rush into it b/c there are side-affects, plus it's likely a lifelong commitment and can be expensive.