It is impossible to understand impedance and reactance without understanding the math used to describe these two phenomena. If you aren't familiar and comfortable working with the arithmetic of complex numbers you will never "get it" when it comes to understanding complex impedance and its relationship to reactance and resistance. As
@BobK mentioned, there are two kinds of reactance, inductive reactance and capacitive reactance that can combine at a particular frequency (the resonance frequency) to produce virtually zero total reactance (series connection of inductor and capacitor) or almost infinite total reactance (parallel connection of inductor and capacitor).
It is perhaps unfortunate that reactance is measured in the same units as resistance because the two are completely different, both in principle and in practice. A reactance stores electrical energy and does not dissipate real power. A resistance consumes electrical energy and dissipates real power (as heat) in doing so.
When considering a sinusoidal voltage across, and a current through, a component exhibiting reactance, the current and voltage are always ninety degrees out of phase with each other. This is effect is modeled mathematically by considering reactance to be represented as an imaginary number, j = sq.rt. (-1), multiplied by a real number, X, positive for inductive reactance and negative for capacitive reactance. It gets a lot more complicated after that, especially when trying to analyze circuits with resistive and reactive components. But fortunately there are math programs as well as short-cuts that can take most of the pain away.
Learn the basics of complex arithmetic first and then analyze a few circuits involving resistors, capacitors, and inductors. By analyze, I mean apply specified voltage or current sources between various nodes and then determine the resulting voltages and currents between other nodes.
Check your understanding by modeling circuits with any one of several free online simulation programs. Follow up by bread boarding real circuits and making oscilloscope measurements of the voltages and their phase relationships. You will need a variable-frequency sinusoidal audio signal generator to use with your oscilloscope, which can be an el-cheapo digital o-scope kit widely available on eBay. A constant-amplitude sine wave generator is preferable, but even a simple triangle wave generator can produce a "gud enuf" sine wave with diode break-point shaping of the triangular peaks. Google for examples on the Internet.
Note that reactance and impedance are functions of a sinusoidal frequency. While the electrical property of
having a reactance or impedance value exists at
any frequency, the actual value of the reactance or impedance is only defined at a
specific sinusoidal frequency of your choosing.
Good luck in finding your "ah ha!" moment with regard to this subject. I struggled with it for many years as a teenager (sometime near the middle of the last century) because I didn't know, or understand, complex arithmetic. All I had to work with were the scalar "formulas" for inductive and capacitive reactance. I didn't have a clue, for many years, as to how to include resistance in the equation to obtain impedance.