Betty, don't worry about it. People to whom this came naturally think it's simple. For those of us who find it challenging, it's not. But the one thing that's certain: Anxiety floats. When you worry about your buoyancy, your breathing changes and you make yourself more positive, and most of the time, you're so focused on the suit or the wing or whatever that you don't even NOTICE the breathing change.
One thing that was repeatedly recommended to me, and which did seem to help fine tune my buoyancy (long after the gross problems of corking were pretty much gone) was deliberately to spend time hanging in midwater. I don't know whether the ascent issues you are having are coming up an ascent line, on free ascents, or ascents upslope, but if it's mostly in midwater, try just planning to spend the 15 minutes of your dive doing stops at 30, 20 and 10, and just sitting there for a full five minutes. At the beginning, it will be hard, and you'll yo-yo, but if you keep it up, eventually you'll learn how to relax and you'll stabilize. Doc Intrepid told me, three plus years ago, that 90% of buoyancy is mental, and he was right. When I stopped psyching myself out, things got much better.
Oh I am quite certain they did teach it . . . and obviously it didn't stick with me. Can't blame the trainer when the trainee didn't remember it among the 1,000 other little things she was trying to learn in cert.
