I saw this question online recently. The number of results for this question on Google is 6.1 million so it’s worth answering.
Is jazz improvisation hard? YES.
There are two forms of jazz soloing. One form is comprised of stringing together scales, arpeggios, memorized licks, and patterns in order to skillfully weave notes over the chord changes to tunes. To someone less familiar with jazz, it sounds almost identical to truly improvised jazz. It’s like putting together a puzzle in order to hold up the final painting, which is the jazz solo.
The other form is true improvisation in which the musician composes music on the spot. He is swiftly and intuitively bruching away in readl time so that at the end of that two or three minute improvisation, a final masterpiece painting has emerged for all to enjoy.
As jazz got more sophisticated in the 1960s, musicians became more and more skilled at pure improvisation. Charlie Parker was arguably the greatest jazz musician ever. But even he played repeated patterns. Think of those patterns like bricks. Parker created the mortar between them. His genius was in his inspired and fluid way of composing great melodies over chord changes where the patterns didn’t sound like patterns. Like a bird, he seemingly soared through the air without effort. Bird was a great jazz improvisor.
Paul Bley and Ornette Coleman were two of the first pure improvisers. The great bass player Steve Swallow tells of his first gig with Paul Bley. Steve tried a few times to get from Paul what they would be playing, but paul wouldn’t say. As they collected on stage, Paul started playing and Steve knew he’d just have to make his way through figuring it out, so he played his first note. That night turned out to create an epiphany for Steve.
Regardless of the type of jazz player you choose to be, the musician must be highly skilled on their instrument in order to create a jazz solo using each method I described above. A good jazz soloist must be at times expressive and at other times, burning fast. They must have an extraordinary sense of rhythm and know the form of tunes inside and out.
So, even though there are distinct differences in how jazz musicians solo/improvise, yes, it’s hard.