Hi there, superior vena cava obstruction may be the cause of developing significant collateral circulation on the anterior chest wall and axillary (armpit) region. The collateral circulation will be observable on the anterior chest wall as new vessels. This needs medical attention. Other signs of superior vena cava obstruction may manifest as edema of the face (swelling).
What lydia said (with the exception of boobs being further south, of course...mine are just the same as always....tee hee...end sarcasm)
The only thing I'll add is veins will be much more prominent after a hot shower, that's normal.
I don't think it's any cause for concern...I have some pretty dark and obvious veins on my chest and shoulders too, and that location could be something you may not have paid very close attention to, I know I don't.
Get them checked, my guess is, it is perfectly normal and just something you never paid attention to before.
If these veins are as prominent as you say, it's hard to believe you wouldn't have noticed them before this.
I have noticed, in the past couple of years, "new" veins on MY breasts, some are very noticable and the smaller ones are real "squiggly" looking. A couple of them trail off towards my shoulders. I haven't freaked out for a couple of reasons..........I'm substantially older than you, (61) my breasts are no longer where they used to be, I mean, they're still in the front, they're just a wee bit further south than they use to be AND I nused two kids. I've also had yearly mammograms and I see my doctor for an annual. Nobody has said anything about my "boob veins," so I'm assuming they are nothing to be concerned about.
In my humble and non-medical opinion, the symptoms you're having........ higher than normal BP, that "can't get enough air" feeling, are being caused by anxiety related to these veins. You also have SVT which IS affected by stress. So, the best thing you could do is see your doctor or OB/GYN and find out what's going on.
I don't know of any disease that has "boob veins" as a major OR minor symptom. It's probably just your body.
Put your mind at ease, see your doc.
Peace
Greenlydia