Hello, thanks for the query to H.C.M. Forum.
Diabetic from the last 8 years,
Age 40 years,
Pain left side of chest,
Pain increases when lying.
All these symptoms are indicative of pain in the heart, diabetic are prone to heart ailment.
2nd reason may be pain in the lung of left side.
Get in blood examination for
lipid profile, sugar, S G O T,S G P T, CPK.
Treadmill test will reveal the condition of heart.
If possible please get in
ANGIOGRAPHY of arteries of heart for correct findings.
Take treatment accordingly.
Good luck.
Dr. HET