0 to 2 VDC to 4-20 mA using OP07
Before simulating, which is really just a virtual version of building it and b*ggering around with it on the bench, you should design the circuit to do what you want. 

One thing that leaps out from a glance at your schematic is that you are not respecting the input common mode range of the OP-07. It is only guaranteed to work to within 2V (1V typically) of the positive supply and you are at 1V with a 4mA output. You can solve this by adding a couple of series diodes between the 12V supply and the R11/R14 junction. That will reduce the output compliance range by two diode drops, of course. 

Nonlinearity (severe nonlinearity anyway) is a red flag that indicates something is saturating or is going out of range. You will also see nonlinearity if  your load resistance is too high (but in your case you have it almost shorted). You will want to test it from near zero to something like 200 ohms. 

This is not the sort of thing that simulation can always find because the model will not typically represent worst-case characteristics, more likely "typical" or sometimes better than typical. This can lead to the unfortunate situation where the simulation works perfectly, the prototype works on the bench, and when you order 1,000 made at the factory 20% of them fail the final test, and a fraction of the remainder are marginal, perhaps at temperature extremes.  

Normally on 4-20mA transmitter circuits we would like to have overrange capability from perhaps 3.6mA to maybe 22+mA in order to indicate situations such as a broken sensor or loss of power. 

For simulation I would recommend LTspice, which is a free download, rather than MATLAB simulation.