Should I be concerned about my heart or lungs?

Should I be concerned about my heart or lungs? Can you recommend tests to rule out conditions?

I feel deep, broad pressure along the left side of my chest – under the armpit and lateral to the nipple – spanning below ribs 3,4 & 5. The pressure is only present when I am laying down. It’s worse if I lay on my left side. I have to sleep on my right side. I use to sleep on both sides and back but over the past 10 years I haven’t been able to sleep on my left side. I feel the pressure immediately upon laying down and the pressure builds over time from noticeable to uncomfortable. In addition, occasionally I would develop a knot of constant muscle pain in my mid back, left side only, between the inferior scapula angle and the spin approximately lateral to T6 or 7. I’m concerned this pressure is an inflammatory condition related to my heart and I’m looking for health advice.  I’m wondering with my history of asthma could this be more of a condition originating with my lungs (pulmonary vein / blood flow between the lungs and heart) or my heart? I’ve just learned of the term cardiac asthma and am wondering if this could be a factor? Also what tests should I take to rule out concerning conditions?

Thanks in advance,
Ps please see below for health history

Health history:
Age: 42, Sex: male, weight –148lbs, height 5’,4”
History of allergies – runny nose, sneezing, coughing, sinus infections as a teenager but through diet changes I have reduced these conditions from chronic to seasonal (autumn) – only sneezing, runny nose.
Low back pain & Knee pain (chronic as a teenager reduced by Tai Chi / exercise to intermittent back pain after sleeping for several hours.)
Pneumonia – twice at age 16 and 41 (left lung)
Migratory, dry, cracked skin sores along finger joints, left elbow
Cholesterol: 166; LDL 119 (high), HDL 29 (low)
Blood pressure: 90 / 60 mmHg – tends to be low
I tend to have a damp/phlegm constitution. My energy has always been on the low side. I had a poor diet as a child. My left radial pulse has chronically felt deeper/weaker than my right.
Asthma (Adult onset) – starting in early 30’s
Current asthma condition – originally occurring in the winter, recently is lasting all year only this past year. I control it with an inhaler. I only need to take the inhaler at night or if I get extremely fatigued which is rare. I can’t eat a heavy meal in the evening or I begin coughing and wheezing. Asthma symptoms: slight wheezing upon immediately laying down to go to bed, being upright it immediately can change. The wheezing disturbs my sleep. I feel like my breathing is weak and shallow. If I breathe strongly the wheezing decreases or is not apparent at all. I recently lived in Hawai’i for 3 years symptom free of allergies.

[Sunny602]

What comes to mind when I read that you have wheezing upon lying down and can't eat heavy meals or else you have wheezing or coughing as well is GERD. Have the doctors considered GERD (reflux disease) in you? You said that your wheezing gets better upon being upright...with GERD, reflux material can get into the lungs thus causing wheezing and asthma symptoms. This is just a thought...try sleeping with your head elevated and see what happens. Hope this helps..Sunny