How would I fix my lateral incisors that have shifted suddenly as an adult back to pre-braces?

Hello, I am 29 and had braces as a teenager for one or two years. As my lateral incisors were crooked and coming in from an angle. Other than that, my teeth were straight with minimal over bite. I had bottoms Braces for the minimal over bite for less then a year. I was given a temporary retainer to wear at night for a year or a few. I don't believe I kept up with this as I should have. But my teeth have remained straight up until recently. I have noticed they have shifted a lot in the past year again where my lateral incisors are noticeable crooked especially the view from the side. I can post pictures if needed. My four first bottom teeth have become a little shifted as well which is surprising as they were never like that before braces even. I read that teeth shift a little when older, but do not understand why the drastic noticeable shift with in the last year as nothing in my lifestyle would have contributed. I have also had my wisdom teeth removed as a teenager so this can't be the cause. The cause ISNT the issue, it is how can I fix this. Would a retainer help with adjusting the change? Or would invasalign be the best approach. How many trays would you think I would need for my specific issue and for how long? If that were to be the only solution would they again shift eventually back to crooked after I completed the invasalign process? How much does this cost normally and would my dental/health insurance cover this. As my teeth have been hurting as of late because of this shift I think. I will not go the metal braces route as I am in sales and see customers daily. I know veneers can be an option but maybe more costly and I like the idea of having my own teeth if doable. I hoping sometbig as simple as wearing a retainer at night can be the solution... Would my dentist be able to provide this information or would I need to go straight to an ortho? Please let me know how to post pictures or where to send them too so you can get a better idea. Ideally I would love my bottom teeth to be adjusted back to straight as well, but my main concern is my two teeth on top. It is a major bummer as I have been blessed with nice looking teeth and a good smile and this has really made me self conscious. Please advice. Thanks!