Mine was on the left side and deep, almost to the chest wall and inside of the breast so kind of right over the heart. Did initial setup (CT) with markings but then put in for first treatment and they didn’t like how it was in the machine so redid it and postponed first treatment a couple days. They gave me Aquaphor to use daily and for 1 month after finish. After I stopped, there were changes to color and skin texture of the affected breast and surgeons office said to restart moisturizing tissue, maybe lifetime (the comment being “radiation, the gift that keeps on giving”). Able to stop after about a year and only thing now (2 yrs) is lighter pigment to skin. I did have lung damage in 2 places, not causing any problems but last pet scan (Feb) actually noted that was better. Did discuss heart with cardiologist and he was unconcerned- noted it can take 5 years or more to see any cardiac effects and it’s extremely rare. As to the fatigue, not sure I can help because radiation was started 1 month after completion of chemo so can’t tell which caused it. Still having problems but currently is it still from chemo, from combination of chemo/radiation or just these nasty ai meds causing the problems.