“The sharp thorn often produces delicate roses.” -Ovid
Ever had a problem that just wouldn’t go away? Paul described the thorn in his flesh as a messenger from Satan that tormented him and kept him from becoming proud. This thorn was a weakness that pushed Paul to a greater dependency on Christ. Paul even bragged about his weakness because the end result was strength in Christ (weakness --> dependency on Christ --> strength). Likewise, we can’t beat our thorns (whatever "it" is) on our own. If all you needed was more discipline or to try harder then you’d have beaten it already. Rely on Christ and watch your weakness become strength.
For when I am weak, then I am strong (2 Corinthians 12:10, NIV).