Dear
Welcome to HCM
We understand your concerns
I went through your details. Your ability to hike faster and to have more energy purely depends on your practice and related stamina (provided your physical health is proper). From the given symptoms,
shortness of breath, night time chest ache and heart racing is more corresponding with
anxiety and obsession. You could be worried about your age, health, family and other related problems. You could be stressed due to the same. You could be worried that you are able to do exercise and phsycial activities thrice a week and you worry that it is less. You could be more health conscious.
All the above worries and obsessions combine together and make you obsess. Obsess with your health. When we obsess, we obsess more towards the 'movable' parts of our body. In your case, you are obsessing with 'the movable' part of your body like heart, lungs etc, and become anxious. Such anxiety races your heart beat. That is the possible explanation.
You may consult a physician and have an EKG taken to clear any physiological issues. Then you may
consult a psychologist for having stress disorder / anxiety treatment.
If you require more of my help in this aspect, please use this URL. http://goo.gl/aYW2pR. Make sure that you include every minute detail possible.
Hope this answers your query. Further clarifications are welcome.
Good luck. Take care.