Self-employed (Stock trading at home) income tax and capital gain tax both needed to pay?

Hi, I am a self-employed sole trader doing stock trading at my own home which is my sole source of income in UK Do I need to input my stock trading gain/loss at SA103 "Self-employment" and SA108 "capital gain tax"? If yes, under section "Listed shares and securities" in SA108 "capital gain tax", I have filled the information in the box 24 "disposal proceeds", in the box 25 "allowable costs", in the box 26 "gain in the year before lossess" and in the box 27 "losses in the year" So, how should I fill in the relevant information under section "Business Income" in SA103 "Self-employment" ? Should I fill the information in the box 15 "Your return" , in the box 31 "Total expenses" that are in accordance with the figures in the box 24 "disposal proceeds", in the box 25 "allowable costs" under section "Listed shares and securities" in SA108 "capital gain tax" ? Should I fill the information in the box 47 "net profit" under section "Business Income" in SA103 "Self-employment" that is equal to subsctaction of the figure in the box 26 "gain in the year before lossess" from the figure in the box 27 "losses in the year" under section "Listed shares and securities" in SA108 "capital gain tax" If yes, after I filled in the above informations, I found in the tax calculation summary in HMRC online self assessment that I have to pay Income Tax, Capital Gains Tax, and Class 4 National Insurance contributions that both Income Tax and Capital Gains Tax are counted in accordance with my sole stock trading profit acquired at my own home? Or should my tax to be paid only be counted under income tax? It seems my sole stock trading profit are "double-counted" under Income Tax and Capital Gains Tax with two different tax rates... Thanks for your attention, I am looking forward to hearing from you soon.

Hi, may anyone kindly have a clue for my quesiotns? Thanks.

Hi soluble,
As you are self employed (sole trader) you would put your trading profits / losses in SA103 only and not in SA108.  
SA108 is used only for declaring capital gains that arise from the disposal of assets you own, this is very different to buying stock and selling it as a sole trader.
Thank you.

Thanks. What if I accidentally put my trading profits / losses in both SA103 and SA108 for tax yr 2022-2023? Will my tax calculation be amended by HMRC?

Hi
No.  
You will need to amend your tax return yourself.  
If you submitted your return online, you can log into your personal account and amend your tax return from there.  
Alternatively, you can write to
H.M. Revenue and Customs
Self Assessment
BX9 1AS, either in the form of a letter advising which boxes to remove or by submitting an amended SA103 or SA108 or both.  
I regret that we cannot amend these supplementary pages for you by telephone or webchat.