LAD/OM1 mild narrowing

Having some issue when I exercise as I started going for this recently afger 15 years of sedatary . Went to a doctor  and done stresss thaallium 4 years back. It came normal. Still I am getting light pain in the lower rib case and light headness.
Went to doctor and went through CT SCAN ANGIOGRAM. Results are as follows

LMCA/RCA/LCX/RCA/PDA/PLVB/AROTA/CHAMBERS - ARE NOrmal.
LAD- Ostium has a non calcified plaque with very mild narrowing.
OM1- OSTIUM/PROXILA RE NORMAL. mId segement has non calcified plaque with very mild narrowing.
impression- mild CAD

He told me that great population have this kind of issue now days around globe and saying around 40 % of people whose age is more than 45. He said nothing to worry and asked me do excercse and medication
Lipitor - 10 mg, asprin 75mg,betablocar 25 mg through out life.

What is the above result mean from comman ma terms. Please advice

[kenkeith]

There is soft plague (not calcified) narrowing that the origin of the left main artery and considered insginificant...there shouldn't be any pain associated with the mild occlusion.  

There were autopsies of returning military and at their young age were beginning to show occlusions.

There isn't anything in the report that you should be concerned over.  There are many causes for the pain and dizziness you are experiencing.

[Rosewater]

Thanks for your answer