First - warning - new atomizers arrive with primer on them and primer tastes nasty. Blow the atomizer out into a tissue. Then you can rinse the atomizer well, blow and shake out and dry thoroughly. OR you can drip 3-4 drops of juice on the bridge /\, wait for it to soak in a bit, and then vape that off without inhaling (use an empty cart or drip tip), then blow out the atty and repeat. Then re-prime and it should be OK.
Did you get eliquid? The eliquid at hardware vendors can be a bit harsh - it is often 100% PG Chinese juice and PG alone lets through the most of nicotine's skin irritation which you do not want in your lungs. So if you got 100% PG you may want to pick up a bottle of Humco Glycerin at Walmart (Humco says their is all vegetable aka VG - it should be near rubbing alcohol) or the more expensive Wilton's Glycerin near the cake decorating stuff in Michael's crafts. That way, if any of your juice is too harsh you could add a bit of VG to it. It will cut the flavor and nic too but will help keep it from irritating you.
When you order more juice try US juice vendors who offer PG/VG blends - BTW I think Gourmet Vapor's sale goes to midnight tonight 5/11 - 50% off with code gv50 which makes their 5ml juices under $2. They offer every PG/VG combo and you can even create your own flavors. Try some 70pg/30vg. FreedomSmokeUSA and Backwoods Brew are popular places for tobacco vapes.
And I highly recommend some Boge 510 cartomizers. Most people prefer dripping and/or cartomizers by far over using carts with an atomizer. Cartomizers have limited lives (a Boge may work well for 4-14 days) but they vape so nicely and don't need juice as often. As well, they keep each flavor totally separate - no mixing of tastes on an atomizer. I get them at LitecigUSA.net and elsewhere. Try the standard resistance for starting out since you have asthma. I use the standards all the time. The LR ones can also be used on an Ego but are hotter with a harder hit - get used to vaping first them you can try these.
And while you are there get a plastic or delrin drip tip. You can use the drip tip to test juices on the atomizer or as a comfortable mouthpiece on the cartos. If you got a particular tube size Ego atty then you will ned an Ego drip tip for the atty but still a 510 atty for an optional mouthpiece on the cartomizers. You will probably have to leave the cone off the Ego when using a carto (or buy a 510 extension at Goodprophets.com to lift up the carto high enough to poke through the cone well).
Filling a Boge carto - Only put juices you know you like into a carto. Hold a tissue against the threaded end hole and fill totally to start (18+ drops), then do cleanup - clean the threaded end, tilt the opened end down into the tissue and puff in the threaded end to clear the aut channel - I like to see light through it, sop up any loose juice above the stuffing. Then cap (or put drip tip on as a mouthpiece) and let it settle so every single bit of stuffing absorbs some juice so you won't singe the carto. I lay the freshly filled blank on different sides for 15-20 minutes and that is enough with the thin (30% VG or less) juices I use. If you have higher VG you may need to let a carto settle a lot longer.
